WO2010071113A1 - Semiconductor light emission element - Google Patents

Semiconductor light emission element Download PDF

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Publication number
WO2010071113A1
WO2010071113A1 PCT/JP2009/070841 JP2009070841W WO2010071113A1 WO 2010071113 A1 WO2010071113 A1 WO 2010071113A1 JP 2009070841 W JP2009070841 W JP 2009070841W WO 2010071113 A1 WO2010071113 A1 WO 2010071113A1
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Prior art keywords
layer
bonding
bonding layer
light emitting
semiconductor
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PCT/JP2009/070841
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French (fr)
Japanese (ja)
Inventor
宏二 亀井
玲美 大庭
高史 程田
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昭和電工株式会社
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Priority claimed from JP2008318700A external-priority patent/JP2010141262A/en
Priority claimed from JP2008320027A external-priority patent/JP2010147097A/en
Priority claimed from JP2009083126A external-priority patent/JP2010238802A/en
Application filed by 昭和電工株式会社 filed Critical 昭和電工株式会社
Priority to US13/139,642 priority Critical patent/US8829555B2/en
Priority to CN200980150297.7A priority patent/CN102246326B/en
Priority to KR1020117005702A priority patent/KR101257572B1/en
Publication of WO2010071113A1 publication Critical patent/WO2010071113A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/36—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/36—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes
    • H01L33/40—Materials therefor
    • H01L33/42—Transparent materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/26—Materials of the light emitting region
    • H01L33/30—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table
    • H01L33/32—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table containing nitrogen
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/36—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes
    • H01L33/40—Materials therefor

Definitions

  • the present invention relates to a semiconductor light emitting device.
  • GaN-based compound semiconductors have attracted attention as semiconductor materials for short wavelength light emitting devices.
  • GaN-based compound semiconductors include sapphire single crystals, various oxides and III-V compounds as substrates, and metalorganic vapor phase chemical reaction method (MOCVD method) and molecular beam epitaxy method (MBE method). And so on.
  • MOCVD method metalorganic vapor phase chemical reaction method
  • MBE method molecular beam epitaxy method
  • a stacked semiconductor layer having an LED structure composed of an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer is usually formed on a substrate, and the uppermost p A transparent electrode and a bonding pad electrode are formed on the p-type semiconductor layer, and a bonding pad electrode is formed on the n-type semiconductor layer exposed by removing a part of the p-type semiconductor layer and the light emitting layer by etching or the like.
  • Patent Document 1 describes that the pad electrode on the transparent electrode is made of Au / Cr, and that the pad electrode on the n-type nitride semiconductor layer is made of Au / Cr.
  • Cr Since Cr has high bondability with Group III nitride semiconductors such as GaN and transparent electrodes such as ITO (Indium Tin Oxide), it should be used as a component for the bonding layer that bonds the transparent electrode or semiconductor layer to the pad electrode. Can be considered. However, when Cr is used for the bonding layer, depending on the use environment, air or moisture easily enters the bonding layer from the outside, and the air or moisture that has entered the bonding layer decomposes the bonding layer when energized, There is a risk of shortening the device life of the semiconductor light emitting device.
  • Group III nitride semiconductors such as GaN
  • transparent electrodes such as ITO (Indium Tin Oxide)
  • An object of the present invention is to improve the bondability between a transparent electrode or a semiconductor layer and a connection electrode and the reliability of the electrode.
  • a semiconductor light emitting device to which the present invention is applied includes a substrate, a laminated semiconductor layer including a light emitting layer and stacked on the substrate, a transparent electrode including indium oxide and stacked on the stacked semiconductor layer, and a valve action metal.
  • a bonding layer that is stacked on the transparent electrode so that the side in contact with the transparent electrode includes at least one of the selected element and at least one of an oxide or a nitride of the element; And a connection electrode used for electrical connection.
  • the bonding layer contains at least one element selected from the group consisting of Al, Ti, Zn, Zr, Nb, W, Mg, Bi, Si, Hf, and Ta.
  • the bonding layer may include at least one element selected from the group consisting of Al, Ti, Zn, Zr, Nb, W, Mg, Bi, Si, Hf, and Ta.
  • the bonding layer may include at least one element selected from the group consisting of Ta, W, and Ti.
  • the bonding layer includes an oxide of an element
  • the bonding layer may include at least one element selected from the group consisting of Ta, Nb, and Ti.
  • the connection electrode may have a bonding layer made of Au, Al, or an alloy containing any of these metals.
  • connection electrode further includes a barrier layer stacked between the bonding layer and the bonding layer, and the barrier layer includes Ag, Al, Ru, Rh, Pd, Os, Ir, Pt, Ti, W, Mo, It can be characterized by being made of an alloy containing any one of Ni, Co, Zr, Hf, Ta, Nb or any of these metals. Furthermore, the transparent electrode can be characterized by comprising indium oxide and zinc oxide.
  • the laminated semiconductor layer may be formed of a group III nitride semiconductor.
  • a semiconductor light emitting device to which the present invention is applied includes a substrate, a laminated semiconductor layer formed of a group III nitride semiconductor having a light emitting layer and stacked on the substrate, and a valve metal Junction laminated on one semiconductor layer so as to contain at least one element selected from the above and the side in contact with one semiconductor layer of the laminated semiconductor layers contains at least one of an oxide or nitride of the element And a connection electrode stacked on the bonding layer and used for electrical connection with the outside.
  • the bonding layer includes at least one element selected from the group consisting of Al, Ti, Zn, Zr, Nb, Mg, Bi, Si, Hf, and Ta. can do.
  • the bonding layer may include at least one element selected from the group consisting of Ta, Nb, and Ti.
  • the connection electrode may have a bonding layer made of Au, Al, or an alloy containing any of these metals.
  • connection electrode further includes a barrier layer stacked between the bonding layer and the bonding layer, and the barrier layer includes Ag, Al, Ru, Rh, Pd, Os, Ir, Pt, Ti, W, Mo, It can be characterized by being made of an alloy containing any one of Ni, Co, Zr, Hf, Ta, Nb or any of these metals.
  • a semiconductor light emitting element to which the present invention is applied includes a first semiconductor layer having a first conductivity type, a light emitting layer stacked on the first semiconductor layer, and light emission.
  • a transparent electrode having translucency with respect to the output light and at least one element selected from valve action metals and a side in contact with the transparent electrode include at least one of an oxide or a nitride of the element At least one selected from a first bonding layer stacked on the transparent electrode, a first connection electrode stacked on the first bonding layer and used for electrical connection to the outside, and a valve metal In contact with the first semiconductor layer
  • a second connection electrode used for connection used for connection.
  • the first semiconductor layer is composed of an n-type semiconductor layer having electrons as carriers
  • the second semiconductor layer is composed of a p-type semiconductor layer having holes as carriers.
  • the first bonding layer and the second bonding layer contain at least one element selected from the group consisting of Al, Ti, Zn, Zr, Nb, W, Mg, Bi, Si, Hf, and Ta. It can be characterized by being.
  • the first bonding layer and the second bonding layer can be characterized by including an oxide or nitride of the same element.
  • the first connection electrode and the second connection electrode may be configured to include the same metal or the same alloy.
  • the transparent electrode can be characterized by comprising indium oxide and zinc oxide.
  • the first semiconductor layer, the light emitting layer, and the second semiconductor layer may be made of a group III nitride semiconductor.
  • the adhesiveness of a transparent electrode or a semiconductor layer, and a connection electrode and the reliability of an electrode can be improved.
  • XPS X-ray photoelectron spectroscopy
  • 10 is a TEM (Transmission Electron Microscope) photograph of a cross section of a first electrode in the semiconductor light emitting device of Example 4. It is a figure which shows the manufacturing conditions and evaluation result of the semiconductor light-emitting element in each Example and each comparative example of a 2nd Example. It is a figure which shows the relationship between the various manufacture conditions in Examples 22-32 and Comparative Examples 10 and 11 of a 3rd Example, and the evaluation result regarding adhesiveness. It is a figure which shows the relationship between the various manufacture conditions in Examples 33-38 of Comparative Example 3, and Comparative Examples 12 and 13, and the evaluation result regarding adhesiveness.
  • TEM Transmission Electron Microscope
  • FIG. 1 shows an example of a schematic cross-sectional view of a semiconductor light emitting device (light emitting diode) 1 to which the present embodiment is applied
  • FIG. 2 shows an example of a schematic plan view of the semiconductor light emitting device 1 shown in FIG.
  • FIG. 3 shows an example of a schematic cross-sectional view of the laminated semiconductor layer constituting the semiconductor light emitting element.
  • the semiconductor light emitting device 1 includes a substrate 110, an intermediate layer 120 stacked on the substrate 110, and a base layer 130 stacked on the intermediate layer 120. Further, the semiconductor light emitting device 1 includes an n-type semiconductor layer 140 stacked on the base layer 130, a light-emitting layer 150 stacked on the n-type semiconductor layer 140, and a p-type semiconductor layer stacked on the light-emitting layer 150. 160.
  • the n-type semiconductor layer 140, the light emitting layer 150, and the p-type semiconductor layer 160 are collectively referred to as a laminated semiconductor layer 100 as necessary.
  • the semiconductor light emitting device 1 includes a transparent electrode 170 stacked on the p-type semiconductor layer 160 and a protective layer 180 stacked on the transparent electrode 170.
  • the semiconductor light emitting device 1 includes a first bonding layer 190 stacked on a portion of the transparent electrode 170 that is not covered by the protective layer 180, and a first bonding pad electrode stacked on the first bonding layer 190. 200.
  • the semiconductor light emitting device 1 is formed on a part of the semiconductor layer exposed surface 140c of the n type semiconductor layer 140 exposed by cutting out a part of the p type semiconductor layer 160, the light emitting layer 150, and the n type semiconductor layer 140.
  • a second bonding layer 220 to be stacked, and a second bonding pad electrode 230 to be stacked on the second bonding layer 220 are provided.
  • the protective layer 180 is also formed on the semiconductor layer exposed surface 140c, and the second bonding layer 220 is stacked on a portion of the semiconductor layer exposed surface 140c that is not covered by the protective layer 180.
  • the transparent electrode 170, the first bonding layer 190 stacked on the transparent electrode 170, and the first bonding pad electrode 200 are collectively referred to as a first electrode 210.
  • the second bonding layer 220 and the second bonding pad electrode 230 are collectively referred to as the second electrode 240.
  • the first bonding pad electrode 200 in the first electrode 210 is a positive electrode and the second electrode 240 is a negative electrode, and a laminated semiconductor 100 as an example of a power-supplied body via both (more specifically, Specifically, the light emitting layer 150 emits light by passing a current through the p-type semiconductor layer 160, the light-emitting layer 150, and the n-type semiconductor layer 140).
  • the substrate 110 is not particularly limited as long as a group III nitride semiconductor crystal is epitaxially grown on the surface, and various substrates can be selected and used.
  • substrates can be selected and used.
  • a substrate made of lanthanum strontium oxide aluminum tantalum, strontium titanium oxide, titanium oxide, hafnium, tungsten, molybdenum, or the like can be used.
  • a sapphire substrate having a c-plane As a main surface.
  • an intermediate layer 120 buffer layer is preferably formed on the c-plane of sapphire.
  • an oxide substrate or a metal substrate that is known to cause chemical modification by contact with ammonia at a high temperature can be used, and the intermediate layer 120 can be formed without using ammonia.
  • the intermediate layer 120 when the base layer 130 is formed to form the n-type semiconductor layer 140 described later, the intermediate layer 120 also functions as a coat layer. These methods are effective in preventing chemical alteration of the substrate 110. Further, when the intermediate layer 120 is formed by a sputtering method, the temperature of the substrate 110 can be kept low, so that even when the substrate 110 made of a material that decomposes at a high temperature is used, the substrate 110 is damaged. Each layer can be formed on the substrate without giving.
  • the laminated semiconductor layer 100 is a layer made of, for example, a group III nitride semiconductor. As shown in FIG. 1, the n-type semiconductor layer 140, the light emitting layer 150, and the p-type semiconductor layer 160 are formed on the substrate 110. They are stacked in this order. As shown in FIG. 3, each of the n-type semiconductor layer 140, the light emitting layer 150, and the p-type semiconductor layer 160 may be composed of a plurality of semiconductor layers. Furthermore, the laminated semiconductor layer 100 may further be referred to as including the base layer 130 and the intermediate layer 120.
  • the n-type semiconductor layer 140 conducts electricity in the first conductivity type using electrons as carriers
  • the p-type semiconductor layer 160 conducts electricity in the second conductivity type using holes as carriers.
  • the stacked semiconductor layer 100 can be formed with good crystallinity when formed by the MOCVD method
  • a semiconductor layer having crystallinity superior to that of the MOCVD method can be formed by optimizing the conditions also by the sputtering method. .
  • description will be made sequentially.
  • the intermediate layer 120 is preferably made of polycrystalline Al x Ga 1-x N ( 0 ⁇ x ⁇ 1) , and more preferably those of the single crystal Al x Ga 1-x N ( 0 ⁇ x ⁇ 1) .
  • the intermediate layer 120 can be, for example, made of polycrystalline Al x Ga 1-x N (0 ⁇ x ⁇ 1) and having a thickness of 0.01 to 0.5 ⁇ m. If the thickness of the intermediate layer 120 is less than 0.01 ⁇ m, the intermediate layer 120 may not sufficiently obtain an effect of relaxing the difference in lattice constant between the substrate 110 and the base layer 130.
  • the intermediate layer 120 has a function of reducing the difference in lattice constant between the substrate 110 and the base layer 130 and facilitating formation of a C-axis oriented single crystal layer on the (0001) plane (C plane) of the substrate 110. . Therefore, when the single crystal base layer 130 is stacked on the intermediate layer 120, the base layer 130 with higher crystallinity can be stacked.
  • the intermediate layer forming step is preferably performed, but may not be performed.
  • the intermediate layer 120 may have a hexagonal crystal structure made of a group III nitride semiconductor. Further, the group III nitride semiconductor crystal forming the intermediate layer 120 may have a single crystal structure, and preferably has a single crystal structure. By controlling the growth conditions, the group III nitride semiconductor crystal grows not only in the upward direction but also in the in-plane direction to form a single crystal structure. Therefore, by controlling the film forming conditions of the intermediate layer 120, the intermediate layer 120 made of a crystal of a group III nitride semiconductor having a single crystal structure can be obtained.
  • the buffer function of the intermediate layer 120 works effectively, so that the group III nitride semiconductor formed thereon has a good orientation. It becomes a crystal film having the property and crystallinity.
  • the group III nitride semiconductor crystal forming the intermediate layer 120 can be formed into a columnar crystal (polycrystal) having a texture based on a hexagonal column by controlling the film forming conditions.
  • the columnar crystal consisting of the texture here is a crystal that is separated by forming a crystal grain boundary between adjacent crystal grains, and is itself a columnar shape as a longitudinal sectional shape.
  • the film thickness of the underlayer 130 is preferably 0.1 ⁇ m or more, more preferably 0.5 ⁇ m or more, and most preferably 1 ⁇ m or more.
  • An Al x Ga 1-x N layer with good crystallinity is more easily obtained when the thickness is increased.
  • it is desirable that the underlayer 130 is not doped with impurities. However, when p-type or n-type conductivity is required, acceptor impurities or donor impurities can be added.
  • the n-type semiconductor layer 140 as an example of the first semiconductor layer is preferably composed of an n-contact layer 140a and an n-cladding layer 140b.
  • the n contact layer 140a can also serve as the n clad layer 140b.
  • the base layer 130 described above may be included in the n-type semiconductor layer 140.
  • the n contact layer 140 a is a layer for providing the second electrode 240.
  • the n contact layer 140a is preferably composed of an Al x Ga 1-x N layer (0 ⁇ x ⁇ 1, preferably 0 ⁇ x ⁇ 0.5, more preferably 0 ⁇ x ⁇ 0.1). .
  • the n-contact layer 140a is preferably doped with an n-type impurity, and the n-type impurity is preferably 1 ⁇ 10 17 to 1 ⁇ 10 20 / cm 3 , preferably 1 ⁇ 10 18 to 1 ⁇ 10 19 / cm. When it is contained at a concentration of 3 , it is preferable in that good ohmic contact with the second electrode 240 can be maintained. Although it does not specifically limit as an n-type impurity, For example, Si, Ge, Sn, etc. are mentioned, Preferably Si and Ge are mentioned.
  • the thickness of the n contact layer 140a is preferably 0.5 to 5 ⁇ m, and more preferably set to a range of 1 to 3 ⁇ m. When the thickness of the n-contact layer 140a is in the above range, the crystallinity of the semiconductor is maintained well.
  • n-clad layer 140b is preferably provided between the n-contact layer 140a and the light emitting layer 150.
  • the n-cladding layer 140b is a layer that injects carriers into the light emitting layer 150 and confines carriers.
  • the n-clad layer 140b can be formed of AlGaN, GaN, GaInN, or the like. Alternatively, a heterojunction of these structures or a superlattice structure in which a plurality of layers are stacked may be used.
  • the n-cladding layer 140b is formed of GaInN, it is desirable to make it larger than the band gap of GaInN of the light emitting layer 150.
  • the film thickness of the n-clad layer 140b is not particularly limited, but is preferably 0.005 to 0.5 ⁇ m, and more preferably 0.005 to 0.1 ⁇ m.
  • the n-type doping concentration of the n-clad layer 140b is preferably 1 ⁇ 10 17 to 1 ⁇ 10 20 / cm 3 , more preferably 1 ⁇ 10 18 to 1 ⁇ 10 19 / cm 3 . A doping concentration within this range is preferable in terms of maintaining good crystallinity and reducing the operating voltage of the device.
  • n-cladding layer 140b is a layer including a superlattice structure, a detailed illustration is omitted, but an n-side first layer made of a group III nitride semiconductor having a thickness of 100 angstroms or less and It may include a structure in which an n-side second layer made of a group III nitride semiconductor having a composition different from that of the n-side first layer and having a film thickness of 100 angstroms or less is stacked. Further, the n-cladding layer 140b may include a structure in which n-side first layers and n-side second layers are alternately and repeatedly stacked. The GaInN and GaN alternate structures or GaInN having different compositions. It is preferable that they have an alternating structure.
  • a single quantum well structure or a multiple quantum well structure can be employed.
  • a well layer 150b having a quantum well structure as shown in FIG. 3 a group III nitride semiconductor layer made of Ga 1-y In y N (0 ⁇ y ⁇ 0.4) is usually used.
  • the film thickness of the well layer 150b can be set to a film thickness at which a quantum effect can be obtained, for example, 1 to 10 nm, and preferably 2 to 6 nm from the viewpoint of light emission output.
  • the Ga 1-y In y N is used as the well layer 150b, and Al z Ga 1-z N (0 ⁇ z ⁇ 0) having a larger band gap energy than the well layer 150b. .3) is defined as a barrier layer 150a.
  • the well layer 150b and the barrier layer 150a may or may not be doped with impurities by design.
  • the p-type semiconductor layer 160 as an example of the second semiconductor layer is generally composed of a p-cladding layer 160a and a p-contact layer 160b.
  • the p contact layer 160b can also serve as the p clad layer 160a.
  • the p-cladding layer 160a is a layer that performs confinement of carriers in the light emitting layer 150 and injection of carriers.
  • the p-cladding layer 160a is not particularly limited as long as it has a composition larger than the band gap energy of the light-emitting layer 150 and can confine carriers in the light-emitting layer 150, but is preferably Al x Ga 1-x N. (0 ⁇ x ⁇ 0.4).
  • the p-cladding layer 160a is made of such AlGaN from the viewpoint of confining carriers in the light-emitting layer 150.
  • the thickness of the p-cladding layer 160a is not particularly limited, but is preferably 1 to 400 nm, and more preferably 5 to 100 nm.
  • the p-type doping concentration of the p-cladding layer 160a is preferably 1 ⁇ 10 18 to 1 ⁇ 10 21 / cm 3 , more preferably 1 ⁇ 10 19 to 1 ⁇ 10 20 / cm 3 . When the p-type dope concentration is in the above range, a good p-type crystal can be obtained without reducing the crystallinity.
  • the p-cladding layer 160a may have a superlattice structure in which a plurality of layers are stacked, and preferably has an alternating structure of AlGaN and AlGaN or an alternating structure of AlGaN and GaN.
  • the p contact layer 160 b is a layer for providing the first electrode 210.
  • the p contact layer 160b is preferably Al x Ga 1-x N (0 ⁇ x ⁇ 0.4).
  • Al composition is within the above range, it is preferable in that good crystallinity and good ohmic contact with the first electrode 210 can be maintained.
  • a p-type impurity (dopant) is contained at a concentration of 1 ⁇ 10 18 to 1 ⁇ 10 21 / cm 3 , preferably 5 ⁇ 10 19 to 5 ⁇ 10 20 / cm 3 , good ohmic contact can be obtained. It is preferable in terms of maintenance, prevention of crack generation, and good crystallinity.
  • the thickness of the p contact layer 160b is not particularly limited, but is preferably 0.01 to 0.5 ⁇ m, more preferably 0.05 to 0.2 ⁇ m. When the film thickness of the p contact layer 160b is within this range, it is preferable in terms of light emission output.
  • the first electrode 210 includes the transparent electrode 170, the first bonding layer 190 stacked on the transparent electrode 170, and the first bonding pad electrode stacked on the first bonding layer 190. 200.
  • a transparent electrode 170 is stacked on the p-type semiconductor layer 160.
  • the transparent electrode 170 when viewed in plan, has a p-type semiconductor layer 160 partially removed by means such as etching to form the second electrode 240.
  • the present invention is not limited to such a shape, and may be formed in a lattice shape or a tree shape with a gap.
  • the structure of the transparent electrode 170 can be used without any limitation, including a conventionally known structure.
  • the transparent electrode 170 preferably has a small contact resistance with the p-type semiconductor layer 160. Moreover, in this semiconductor light emitting element 1, since the light from the light emitting layer 150 is taken out to the side where the first electrode 210 is formed, it is preferable that the transparent electrode 170 has excellent light transmittance. Furthermore, the transparent electrode 170 preferably has excellent conductivity in order to diffuse current uniformly over the entire surface of the p-type semiconductor layer 160.
  • an oxide conductive material containing In is used as the transparent electrode 170.
  • a part of the oxide containing In is preferable in that both light transmittance and conductivity are superior to other transparent conductive films.
  • the conductive oxide containing In for example, ITO (indium tin oxide (In 2 O 3 —SnO 2 )), IZO (indium zinc oxide (In 2 O 3 —ZnO)), IGO (indium gallium oxide (In 2 O 3 —Ga 2 O 3 )), ICO (indium cerium oxide (In 2 O 3 —CeO 2 )) and the like.
  • a dopant such as fluorine may be added.
  • the transparent electrode 170 can be formed by providing these materials by conventional means well known in the art. In addition, after forming the transparent electrode 170, thermal annealing may be performed for the purpose of making the transparent electrode 170 transparent.
  • the transparent electrode 170 may have a crystallized structure, and in particular, a translucent material containing an In 2 O 3 crystal having a hexagonal crystal structure or a bixbite structure (for example, ITO or IZO etc.) can be preferably used.
  • a translucent material containing an In 2 O 3 crystal having a hexagonal crystal structure or a bixbite structure for example, ITO or IZO etc.
  • ITO or IZO etc. a translucent material containing an In 2 O 3 crystal having a hexagonal crystal structure
  • a bixbite structure for example, ITO or IZO etc.
  • the ZnO concentration in IZO is preferably 1 to 20% by mass, and more preferably 5 to 15% by mass. 10% by mass is particularly preferable.
  • the film thickness of the IZO film is preferably in the range of 35 nm to 10000 nm (10 ⁇ m) at which low specific resistance and high light transmittance can be obtained. Furthermore, from the viewpoint of production cost, the thickness of the IZO film is preferably 1000 nm (1 ⁇ m) or less.
  • the patterning of the IZO film is preferably performed before the heat treatment process described later.
  • the amorphous IZO film becomes a crystallized IZO film, which makes etching difficult compared to the amorphous IZO film.
  • the IZO film before heat treatment is in an amorphous state, it can be easily and accurately etched using a known etching solution (ITO-07N etching solution (manufactured by Kanto Chemical Co., Inc.)).
  • the amorphous IZO film may be etched using a dry etching apparatus. At this time, Cl 2 , SiCl 4 , BCl 3 or the like can be used as an etching gas.
  • the amorphous IZO film includes, for example, an IZO film including a hexagonal structure In 2 O 3 crystal and a bixbite structure In 2 O 3 crystal by performing heat treatment at 500 ° C. to 1000 ° C. and controlling the conditions. An IZO film can be formed. Since an IZO film containing an In 2 O 3 crystal having a hexagonal crystal structure is difficult to etch as described above, it is preferable to perform a heat treatment after the above etching process.
  • Heat treatment of the IZO film is preferably performed in an atmosphere containing no O 2, as the atmosphere containing no O 2, or an inert gas atmosphere such as N 2 atmosphere, or an inert gas such as N 2 and with H 2 etc. can be mentioned a mixed gas atmosphere, it is desirable that the mixed gas atmosphere of N 2 atmosphere or N 2 and H 2,.
  • the heat treatment of the IZO film is performed in an N 2 atmosphere or a mixed gas atmosphere of N 2 and H 2 , for example, the IZO film is crystallized into a film containing In 2 O 3 crystal having a hexagonal structure, It is possible to effectively reduce the sheet resistance of the IZO film.
  • the heat treatment temperature of the IZO film is preferably 500 ° C. to 1000 ° C.
  • the IZO film When heat treatment is performed at a temperature lower than 500 ° C., the IZO film may not be sufficiently crystallized, and the light transmittance of the IZO film may not be sufficiently high. When heat treatment is performed at a temperature exceeding 1000 ° C., the IZO film is crystallized, but the light transmittance of the IZO film may not be sufficiently high. In addition, when heat treatment is performed at a temperature exceeding 1000 ° C., the semiconductor layer under the IZO film may be deteriorated.
  • the crystal structure in the IZO film differs depending on the film formation conditions, heat treatment conditions, and the like.
  • the transparent electrode 170 is not limited to a material in terms of adhesiveness to the adhesive layer, but is preferably a crystalline material, and particularly in the case of crystalline IZO, a bixbite crystal structure.
  • IZO containing an In 2 O 3 crystal or IZO containing a hexagonal In 2 O 3 crystal may be used.
  • IZO containing In 2 O 3 crystal having a hexagonal structure is preferable.
  • an IZO film crystallized by heat treatment has better adhesion to the first bonding layer 190 and the p-type semiconductor layer 160 than an amorphous IZO film. Is very effective.
  • the first bonding layer 190 as an example of the bonding layer is laminated between the transparent electrode 170 and the first bonding pad electrode 200 in order to increase the bonding strength of the first bonding pad electrode 200 to the transparent electrode 170.
  • the first bonding layer 190 has a light-transmitting property so as to transmit light from the light emitting layer 150 that is transmitted through the transparent electrode 170 and irradiated to the first bonding pad electrode 200 with low loss. Preferably it is.
  • the first bonding layer 190 is preferably formed of a valve metal (valve metal), and is selected from the group consisting of Al, Ti, Zn, Zr, W, Nb, Mg, Bi, Si, Hf, and Ta. It is more preferable that the transparent electrode 170 is laminated so that the side containing at least one element and in contact with the transparent electrode 170 contains at least one of a nitride or an oxide of these elements. Further, a structure including a partially nitrided or partially oxidized metal made of these elements may be used. Thereby, compared with the case where the 1st joining layer 190 is comprised with the valve action metal itself, the joint strength of the transparent electrode 170 and the 1st bonding pad electrode 200 can be improved more.
  • a valve metal valve metal
  • the first bonding layer 190 includes at least one element selected from the group consisting of Ta, W, and Ti, and on the transparent electrode 170 so that the side in contact with the transparent electrode 170 includes a nitride of these elements. More preferably, they are laminated. In addition, a structure including a part of the element metal nitrided may be used. This is because the nitriding portion in the bonding layer metal improves the bonding strength with the transparent electrode 170 that is a metal oxide.
  • metals such as Ta, W, and Ti have the property that they are difficult to ionize among valve metals, and therefore, by including these nitridated metals, the bonding metal element is formed by an electrochemical reaction in the presence of water (moisture). Can be prevented from being ionized and eluted, which is preferable. Thereby, the bonding strength of the first bonding pad electrode 200 to the transparent electrode 170 can be significantly increased.
  • the first bonding layer 190 may be made of a valve action metal nitride, but at least partially, locally or thinly in contact with the transparent electrode 170 is a valve action metal nitride. What is necessary is just to be formed. Therefore, the first bonding layer 190 may be formed of a valve action metal nitride layer formed on the transparent electrode 170 side and a valve action metal layer formed on the first bonding pad electrode 200 side. .
  • the first bonding layer 190 is preferably a thin film having a thickness in the range of 10 angstroms to 2000 angstroms, more preferably in the range of 20 angstroms to 1000 angstroms. Thereby, the light from the light emitting layer 150 can be effectively transmitted without being blocked. Note that if the thickness is less than 10 angstroms, the strength of the first bonding layer 190 is lowered, which may reduce the bonding strength of the first bonding pad electrode 200 to the transparent electrode 170.
  • the thickness of the metal nitride layer in the first bonding layer 190 is preferably about 5 to 50 angstroms.
  • the thickness of the metal nitride layer is 200 angstroms or more, the light transmittance and the reflectance are lowered, which is not preferable.
  • the first bonding layer 190 includes at least one element selected from the group consisting of Ta, Nb, and Ti, and on the transparent electrode 170 so that the side in contact with the transparent electrode 170 includes an oxide of these elements. More preferably, they are laminated. Moreover, it is good also as a structure containing what oxidized the metal which consists of these elements partially. This is because the oxidized portion in the metal constituting the first bonding layer 190 improves the bonding strength with the transparent electrode 170 that is a metal oxide.
  • metals such as Ta, Nb, and Ti have the property that they are difficult to ionize among valve metals.
  • bonding metal elements can be formed by an electrochemical reaction in the presence of water (moisture). Can be prevented from being ionized and eluted, which is preferable. Thereby, the bonding strength of the first bonding pad electrode 200 to the transparent electrode 170 can be significantly increased.
  • the first bonding layer 190 may be composed of an oxide of the valve action metal, but the oxide layer of the valve action metal is at least partially, locally or thinly in contact with the transparent electrode 170. What is necessary is just to be formed. Accordingly, the first bonding layer 190 may be formed of a valve action metal oxide layer formed on the transparent electrode 170 side and a valve action metal layer formed on the first bonding pad electrode 200 side. .
  • the first bonding layer 190 is preferably a thin film having a thickness in the range of 5 angstroms to 1000 angstroms, more preferably in the range of 10 angstroms to 400 angstroms.
  • the thickness is less than 5 angstroms, the strength of the first bonding layer 190 is lowered, and thus the bonding strength of the first bonding pad electrode 200 to the transparent electrode 170 may be lowered.
  • the thickness of the metal oxide layer in the first bonding layer 190 is preferably about 5 to 50 angstroms. If it is 5 angstroms or less, the effect of improving the bonding strength with the transparent electrode 170 is reduced, and if it is 50 angstroms or more, the conductivity between the first bonding layer 190 and the transparent electrode 170 may be lowered.
  • the first bonding pad electrode 200 as an example of the connection electrode and the first connection electrode includes a first barrier layer 200a and a first bonding layer 200b in order from the transparent electrode 170 side. It consists of the laminated body laminated
  • the first barrier layer 200a as an example of the barrier layer has a function of blocking migration of elements forming the first bonding layer 200b, and the first bonding layer 200b as an example of the bonding layer is used for supplying power. There is an effect of improving the adhesion to the external terminal material.
  • first bonding pad electrode 200 may have a single-layer structure including only the first barrier layer 200a, and the first bonding pad electrode 200 is provided between the first barrier layer 200a and the first bonding layer 200b.
  • Another barrier layer that enhances the strength of the entire bonding pad electrode 200 may be further inserted to form a three-layer structure.
  • a barrier layer may be inserted instead of the first barrier layer 200a to form a two-layer structure.
  • the first barrier layer 200a shown in FIG. 1 has a role of enhancing the strength of the first bonding pad electrode 200 as a whole. For this reason, it is preferable to use a relatively strong metal material, for example, Ag, Al, Ru, Rh, Pd, Os, Ir, Pt, Ti, W, Mo, Ni, Co, Zr, Hf, Ta, One made of an alloy containing any of Nb or any of these metals can be selected.
  • the first barrier layer 200a is preferably made of a highly reflective metal to reflect the light emitted from the light emitting layer 150, and is made of platinum such as Ru, Rh, Pd, Os, Ir, and Pt.
  • the first barrier layer 200a is formed of a metal having a high reflectance, it is desirable that the thickness is 200 to 3000 angstroms. If the first barrier layer 200a is too thin, a sufficient reflection effect cannot be obtained. On the other hand, if it is too thick, there is no particular advantage, and only a long process time and material waste are caused. More preferably, it is 500 to 2000 angstroms.
  • the first barrier layer 200a is in close contact with the first bonding layer 190, so that the light from the light emitting layer 150 is efficiently reflected and the bonding strength with the first bonding pad electrode 200 is increased. This is preferable.
  • the first barrier layer 200 a needs to be firmly bonded to the transparent electrode 170 via the first bonding layer 190. At a minimum, a strength that does not cause peeling in the step of connecting the gold wire to the bonding pad by a general method is preferable.
  • Rh, Pd, Ir, Pt, and an alloy containing at least one of these metals are preferably used as the first barrier layer 200a in view of light reflectivity.
  • the reflectivity of the first bonding pad electrode 200 varies greatly depending on the constituent material of the first barrier layer 200a, but is preferably 60% or more. Further, it is preferably 80% or more, and more preferably 90% or more.
  • the reflectance can be measured relatively easily with a spectrophotometer or the like.
  • a transparent “dummy substrate” made of glass, for example, having a large area is placed in the chamber when forming the bonding pad electrode, and at the same time, the same bonding pad electrode is created on the dummy substrate and measured. be able to.
  • the first bonding layer 200b shown in FIG. 1 is preferably made of Au, Al, or an alloy containing at least one of these metals. Since Au and Al are metals with good adhesion to gold balls that are often used as bonding balls, the use of Au, Al or an alloy containing at least one of these metals improves adhesion to bonding wires. It can be excellent. Of these, Au is particularly desirable.
  • the thickness of the first bonding layer 200b is preferably in the range of 500 angstroms or more and 20000 angstroms or less, and more preferably 5000 angstroms or more and 15000 angstroms or less. If the first bonding layer 200b is too thin, the adhesion to the bonding ball is deteriorated. If the first bonding layer 200b is too thick, no particular advantage is produced and only the cost is increased.
  • the light traveling toward the first bonding pad electrode 200 is reflected by the first barrier layer 200a on the lowermost surface (the surface on the transparent electrode 170 side) of the first bonding pad electrode 200, and part of the light is scattered and laterally Alternatively, the process proceeds in an oblique direction, and a part thereof proceeds directly below the first bonding pad electrode 200.
  • the light that is scattered and travels in the lateral direction or the oblique direction is extracted from the side surface of the semiconductor light emitting element 1 to the outside.
  • the light traveling in the direction immediately below the first bonding pad electrode 200 is further scattered and reflected by the lower surface of the semiconductor light emitting element 1, and the side surface and the transparent electrode 170 (the first bonding pad electrode 200 exists on the side surface). Taken out).
  • the first bonding layer 190 and the first bonding pad electrode 200 laminated thereon can be formed anywhere as long as it is on the transparent electrode 170. For example, it may be formed at a position farthest from the second electrode 240 or may be formed at the center of the semiconductor light emitting element 1 or the like. However, if it is formed at a position too close to the second electrode 240, it is not preferable because a short circuit between wires and balls occurs when bonding. Further, as the electrode area of the first bonding pad electrode 200 is as large as possible, the bonding operation is easier, but the emission of light emission is hindered. For example, covering an area that exceeds half the area of the chip surface hinders the extraction of light emission, and the output is significantly reduced. On the other hand, if it is too small, the bonding work becomes difficult and the yield of the product is lowered. Specifically, it is preferably slightly larger than the diameter of the bonding ball, and generally has a circular shape with a diameter of 100 ⁇ m.
  • the second electrode 240 includes the second bonding layer 220 and the second bonding pad electrode 230 stacked on the second bonding layer 220. As shown in FIG. 1, the second electrode 240 is formed on the semiconductor layer exposed surface 140 c of the n-type semiconductor layer 140. As described above, when the second electrode 240 is formed, a part of the light emitting layer 150 and the p-type semiconductor layer 160 is cut off and removed by means such as etching, so that the n-contact layer 140a of the n-type semiconductor layer 140 is removed. The second electrode 240 is formed on the exposed semiconductor layer exposed surface 140c. As shown in FIG.
  • the second electrode 240 has a circular shape when seen in a plan view, but is not limited to such a shape, and may have an arbitrary shape such as a polygonal shape. . Further, the second electrode 240 also serves as a bonding pad and is configured to be able to connect a bonding wire.
  • the second bonding layer 220 includes a second bonding layer 140a and a second bonding layer 140a in order to increase the bonding strength of the second bonding pad electrode 230 to the semiconductor layer exposed surface 140c formed in the n contact layer 140a of the n-type semiconductor layer 140. And the bonding pad electrode 230.
  • the n contact layer 140a corresponds to one semiconductor layer.
  • the second bonding layer 220 is a valve metal (valve metal), that is, a group consisting of Al, Ti, Zn, Zr, W, Nb, Mg, Bi, Si, Hf, and Ta.
  • the semiconductor layer is exposed on the semiconductor layer exposed surface 140c so as to include at least one element selected from the above and the side in contact with the semiconductor layer exposed surface 140c includes at least one of an oxide and a nitride of the element. More preferred. Thereby, the bonding strength between the n contact layer 140a and the second bonding pad electrode 230 can be further improved as compared with the case where the second bonding layer 220 is formed of the valve metal itself.
  • the second bonding layer 220 is made of a material obtained by nitriding at least one element selected from the group consisting of Ta, W, and Ti.
  • the bonding strength of the second bonding pad electrode 230 to the n contact layer 140a can be remarkably increased.
  • the second bonding layer 220 may be formed of a valve action metal nitride layer formed on the n contact layer 140a side and a valve action metal layer formed on the second bonding pad electrode 230 side. Absent. Further, the second bonding layer 220 may be laminated via the n-contact layer 140a side and a known transparent electrode material layer. In this case, the layer of a known transparent electrode material has a function of a bonding layer bonded to the n contact layer 140a side.
  • the second bonding layer 220 is preferably a thin film having a thickness in the range of 10 angstroms to 2000 angstroms, more preferably in the range of 20 angstroms to 1000 angstroms. Note that if the thickness is less than 10 angstroms, the strength of the second bonding layer 220 is decreased, which is not preferable because the bonding strength of the second bonding pad electrode 230 to the n contact layer 140a is decreased.
  • the second bonding layer 220 is made of an oxide of at least one element selected from the group consisting of Ta, Nb, and Ti.
  • the bonding strength of the second bonding pad electrode 230 to the n contact layer 140a can be significantly increased by using an oxidized metal such as Tb, Nb, or Ti.
  • the second bonding layer 220 may be formed of a valve action metal oxide layer formed on the n contact layer 140a side and a valve action metal layer formed on the second bonding pad electrode 230 side. Absent. Further, the second bonding layer 220 may be laminated via the n-contact layer 140a side and a known transparent electrode material layer. In this case, the layer of a known transparent electrode material has a function of a bonding layer bonded to the n contact layer 140a side.
  • the second bonding layer 220 is preferably a thin film having a thickness in the range of 5 angstroms to 1000 angstroms, more preferably in the range of 10 angstroms to 400 angstroms. Note that if the thickness is less than 5 angstroms, the strength of the second bonding layer 220 is lowered, and as a result, the bonding strength of the second bonding pad electrode 230 to the n-contact layer 140a is not preferable.
  • the second bonding pad electrode 230 as an example of the second connection electrode includes a second barrier layer 230a and a second bonding layer in order from the n contact layer 140a (see FIG. 3) side. 230b is laminated.
  • the second bonding pad electrode 230 may have a single-layer structure including only the second barrier layer 230a, and the second bonding pad electrode 230 is provided between the second barrier layer 230a and the second bonding layer 230b.
  • Another barrier layer that enhances the strength of the entire bonding pad electrode 230 may be further inserted to form a three-layer structure.
  • a barrier layer may be inserted instead of the second barrier layer 230a to form a two-layer structure.
  • the second barrier layer 230a shown in FIG. 1 has a role of enhancing the strength of the entire second bonding pad electrode 230, similarly to the first barrier layer 200a. For this reason, it is preferable to use a relatively strong metal material, for example, Ag, Al, Ru, Rh, Pd, Os, Ir, Pt, Ti, W, Mo, Ni, Co, Zr, Hf, Ta, One made of an alloy containing any of Nb or any of these metals can be selected.
  • the second barrier layer 230a is made of a platinum group metal such as Ru, Rh, Pd, Os, Ir, Pt, Al, Ag, Ti, and the like, like the first barrier layer 200a. More preferably, it is made of an alloy containing at least one of these metals.
  • the second barrier layer 230a is in close contact with the second bonding layer 220 in terms of enhancing the bonding strength with the second bonding pad electrode 230.
  • the second barrier layer 230 a needs to be firmly bonded to the n contact layer 140 a via the second bonding layer 220.
  • a strength that does not cause peeling in the step of connecting the gold wire to the bonding pad by a general method is preferable.
  • Rh, Pd, Ir, Pt and an alloy containing at least one of these metals are preferably used as the second barrier layer 230a.
  • the second bonding layer 230b shown in FIG. 1 is preferably made of Au, Al, or an alloy containing at least one of these metals. Since Au and Al are metals with good adhesion to gold balls that are often used as bonding balls, the use of Au, Al or an alloy containing at least one of these metals improves adhesion to bonding wires. It can be excellent. Of these, Au is particularly desirable.
  • the thickness of the second bonding layer 230b is preferably in the range of 500 angstroms or more and 20000 angstroms or less, and more preferably 5000 angstroms or more and 15000 angstroms or less. If the second bonding layer 230b is too thin, the adhesion to the bonding ball is deteriorated. If the second bonding layer 230b is too thick, no particular advantage is produced and only the cost is increased.
  • the second bonding layer 220 and the second bonding pad electrode 230 laminated thereon can be formed anywhere as long as it is on the semiconductor layer exposed surface 140c of the n contact layer 140a. However, from the viewpoint of ease of bonding work, it is preferably slightly larger than the diameter of the bonding ball, and is generally circular with a diameter of 100 ⁇ m.
  • the first bonding layer 190 and the second bonding layer 220 are formed in the same process, and the first bonding pad electrode 200 and the second bonding pad are formed.
  • the electrode 230 is formed in the same process. Therefore, the first bonding layer 190 and the second bonding layer 220 have the same configuration, and the first bonding pad electrode 200 and the second bonding pad electrode 230 have the same configuration. .
  • the step of forming the laminated semiconductor layer 100 including the light emitting layer 150 on the substrate 110 and the semiconductor layer exposed surface 140c by cutting out part of the laminated semiconductor layer 100 are formed. Forming the first electrode 210 on the upper surface 160c of the stacked semiconductor layer 100, and forming the second electrode 240 on the exposed surface 140c of the semiconductor layer.
  • the step of forming the laminated semiconductor layer 100 including the light emitting layer 150 includes an intermediate layer forming step for forming the intermediate layer 120, an underlayer forming step for forming the underlayer 130, and an n-type for forming the n-type semiconductor layer 140.
  • the method for manufacturing the semiconductor light emitting device 1 to which the present embodiment is applied may further include an annealing step for performing a heat treatment on the obtained semiconductor light emitting device after the electrode forming step, if necessary. is there.
  • the laminated semiconductor layer forming step includes an intermediate layer forming step, a base layer forming step, an n-type semiconductor layer forming step, a light emitting layer forming step, and a p-type semiconductor layer forming step.
  • a substrate 110 such as a sapphire substrate is prepared and subjected to pretreatment.
  • the pretreatment can be performed by, for example, a method in which the substrate 110 is placed in a chamber of a sputtering apparatus and sputtering is performed before the intermediate layer 120 is formed.
  • pretreatment for cleaning the upper surface may be performed by exposing the substrate 110 to Ar or N 2 plasma in the chamber.
  • plasma such as Ar gas or N 2 gas to act on the substrate 110, organic substances and oxides attached to the upper surface of the substrate 110 can be removed.
  • the intermediate layer 120 is stacked on the upper surface of the substrate 110 by sputtering.
  • the ratio of the nitrogen flow rate to the nitrogen source flow rate in the chamber and the flow rate of the inert gas is 50% to 100%, preferably 75%. It is desirable to do so.
  • the intermediate layer 120 having columnar crystals (polycrystal) is formed by sputtering, the ratio of the nitrogen flow rate to the nitrogen source flow rate in the chamber and the flow rate of the inert gas is preferably 1% to 50% for the nitrogen source. Is preferably 25%.
  • the intermediate layer 120 can be formed not only by the sputtering method described above but also by the MOCVD method.
  • a single crystal base layer 130 is formed on the upper surface of the substrate 110 on which the intermediate layer 120 is formed.
  • the underlayer 130 may be formed by sputtering or MOCVD.
  • the n-type semiconductor layer 140 is formed by laminating the n-contact layer 140a and the n-cladding layer 140b.
  • the n contact layer 140a and the n clad layer 140b may be formed by a sputtering method or an MOCVD method.
  • the light emitting layer 150 can be formed by either sputtering or MOCVD, but MOCVD is particularly preferable.
  • the barrier layers 150a and the well layers 150b are alternately and repeatedly stacked, and the barrier layers 150a may be stacked in the order in which the barrier layers 150a are disposed on the n-type semiconductor layer 140 side and the p-type semiconductor layer 160 side. .
  • the p-type semiconductor layer 160 may be formed by either a sputtering method or an MOCVD method. Specifically, the p-clad layer 160a and the p-contact layer 160b may be sequentially stacked.
  • ⁇ Semiconductor layer exposed surface forming step> Prior to the formation of the transparent electrode 170, patterning is performed by a known photolithography technique, and a part of the laminated semiconductor layer 100 in a predetermined region is etched to expose a part of the n contact layer 140a, thereby exposing the semiconductor layer exposed surface 140c. To form.
  • the electrode forming process includes a transparent electrode forming process, a bonding layer forming process, a barrier layer forming process, and a bonding layer forming process.
  • Transparent electrode formation process> The transparent electrode 170 is formed on the p-type semiconductor layer 160 that is left without being removed by etching by covering the semiconductor layer exposed surface 140c with a mask, using a known method such as sputtering. In addition, after forming the transparent electrode 170 on the p-type semiconductor layer 160 in advance, the transparent electrode 170 in a predetermined region and a part of the laminated semiconductor layer 100 are etched to form the semiconductor layer. The exposed surface 140c may be formed.
  • a resist (not shown) is applied on the protective layer 180.
  • a protective layer formed on the p-type semiconductor layer 160 is then removed by removing the resist at portions corresponding to the portions where the first bonding pad electrode 200 and the second bonding pad electrode 230 are to be formed.
  • Part of 180 and part of protective layer 180 formed on semiconductor layer exposed surface 140c are exposed to the outside.
  • RIE reactive ion etching
  • the first bonding layer 190 is formed on the exposed surface of the transparent electrode 170 by sputtering, and the second bonding layer 220 is formed on the exposed surface of the semiconductor layer exposed surface 140c.
  • a valve metal nitride layer is formed in the bonding layer forming step.
  • film formation is performed so that the nitride layer of the valve metal is in contact with the transparent electrode 170 and the semiconductor layer exposed surface 140c.
  • a method of forming a valve metal nitride film using a sputtering method for example, there is a method of performing sputtering in an atmosphere containing nitrogen using a metal target made of valve metal.
  • the transparent electrode 170 side of the first bonding layer 190 and the semiconductor layer exposed surface 140c side of the second bonding layer 220 are valve metal nitride layers, and the first barrier layer 200a of the first bonding layer 190 is formed.
  • the side and the second barrier layer 230a side of the second bonding layer 220 are valve metal layers, the nitrogen concentration at the initial stage of the bonding layer forming process is increased, and the nitrogen concentration at the end of the bonding layer forming process is set to the initial value.
  • Another method for forming a valve metal nitride film is, for example, a method in which sputtering is performed in a nitrogen-containing atmosphere or a nitrogen-free atmosphere using a metal nitride target made of valve metal nitride. .
  • the first bonding layer 190 and the second bonding layer 220 can be formed with high coverage regardless of the sputtering material.
  • the same material as that of the first bonding layer 190 and the second bonding layer 220 is also laminated on the cured portion of the resist remaining on the transparent electrode 170 and the semiconductor layer exposed surface 140c.
  • a valve metal oxide layer is formed in the bonding layer forming step.
  • film formation is performed such that the oxide layer of the valve metal is in contact with the transparent electrode 170 and the semiconductor layer exposed surface 140c.
  • a method of forming a valve metal oxide film using a sputtering method for example, a method of performing sputtering in an atmosphere containing oxygen using a metal target made of valve metal can be cited.
  • an atmosphere of sputtering it is preferable that 0.1 volume% or more and 15 volume% or less, more preferably 1.0 volume% or more and 10 volume% or less of oxygen is present with respect to argon.
  • the transparent electrode 170 side of the first bonding layer 190 and the semiconductor layer exposed surface 140c side of the second bonding layer 220 are valve metal oxide layers, and the first barrier layer 200a of the first bonding layer 190 is formed.
  • the side and the second barrier layer 230a side of the second bonding layer 220 are valve metal layers, the oxygen concentration at the initial stage of the bonding layer forming step is increased, and the oxygen concentration at the end of the bonding layer forming step is set to the initial value. Or the oxygen supply may be stopped.
  • Another method for forming the valve metal oxide film is, for example, a method in which sputtering is performed in an oxygen-containing atmosphere or an oxygen-free atmosphere using a metal oxide target made of valve metal oxide. .
  • the first bonding layer 190 and the second bonding layer 220 can be formed with high coverage regardless of the sputtering material.
  • the same material as that of the first bonding layer 190 and the second bonding layer 220 is also laminated on the cured portion of the resist remaining on the transparent electrode 170 and the semiconductor layer exposed surface 140c.
  • the first barrier layer 200a is formed on the first bonding layer 190 and the second barrier layer 230a is formed on the second bonding layer 220 by sputtering.
  • the first barrier layer 200a and the second barrier layer 230a can be formed with high coverage regardless of the sputtering material.
  • the same material as that of the first barrier layer 200a and the second barrier layer 230a is laminated also on the cured portion side of the resist remaining on the transparent electrode 170 and the semiconductor layer exposed surface 140c.
  • the first bonding layer 200b is formed on the first barrier layer 200a and the second bonding layer 230b is formed on the second barrier layer 230a by sputtering.
  • the first bonding layer 200b and the second bonding layer 230b can be formed with high coverage regardless of the sputtering material.
  • the same material as that of the first bonding layer 200b and the second bonding layer 230b is also laminated on the cured portion side of the resist remaining on the transparent electrode 170 and the semiconductor layer exposed surface 140c.
  • the hardened portion of the resist is peeled off by dipping in a resist stripping solution.
  • the first bonding layer 190 and the first bonding pad electrode 200 having the first barrier layer 200a and the first bonding layer 200b are formed on the transparent electrode 170.
  • a second bonding pad electrode 230 having a second bonding layer 220, a second barrier layer 230a, and a second bonding layer 230b is formed on the n contact layer 140a.
  • the semiconductor light emitting device 1 obtained in this way is annealed at 150 ° C. or higher and 600 ° C. or lower, more preferably 200 ° C. or higher and 500 ° C. or lower in a reducing atmosphere such as nitrogen.
  • a reducing atmosphere such as nitrogen.
  • the adhesiveness between the transparent electrode 170 and the first bonding pad electrode 200 via the first bonding layer 190, and the semiconductor layer exposed surface 140c via the second bonding layer 220 and the second bonding layer 220 are exposed. This is performed in order to improve the adhesion with the bonding pad electrode 230.
  • the annealing treatment is not necessarily performed, but it is more preferable to perform the annealing treatment in order to improve the adhesion.
  • the contact surface side between the first bonding layer 190 and the transparent electrode 170 and the second bonding layer 220 and the semiconductor layer exposed is not limited thereto.
  • the transparent electrode forming step the transparent electrode 170 is formed on the p-type semiconductor layer 160, and the obtained transparent electrode 170 is exposed to nitrogen plasma.
  • the protective layer 180 may be formed on the transparent electrode 170 made.
  • the semiconductor light-emitting device 1 can be obtained by performing the above-described bonding layer forming step, barrier layer forming step, and bonding layer forming step.
  • the contact surface side between the first bonding layer 190 and the transparent electrode 170, and the second bonding layer 220 and the semiconductor layer exposed surface 140c is not limited thereto.
  • the transparent electrode forming step the transparent electrode 170 is formed on the p-type semiconductor layer 160, and the oxygen plasma treatment is performed after the obtained transparent electrode 170 is exposed to oxygen plasma.
  • the protective layer 180 may be formed on the transparent electrode 170 made.
  • the semiconductor light-emitting device 1 can be obtained by performing the above-described bonding layer forming step, barrier layer forming step, and bonding layer forming step.
  • the transparent electrode 170 and the first bonding pad electrode 200 are connected via the first bonding layer 190 containing at least one of a nitride or an oxide of valve metal.
  • the adhesion and connection strength of the first bonding pad electrode 200 to the transparent electrode 170 can be improved.
  • the n-contact layer 140a of the n-type semiconductor layer 140 and the second bonding pad electrode 230 are replaced with a second bonding layer 220 containing at least one of a valve metal nitride and an oxide. Therefore, the adhesion and connection strength between the n contact layer 140a and the second bonding pad electrode 230 can be increased.
  • the first connection layer 190 and the second connection layer 220 are configured to include at least one of nitride and oxide of the same valve metal, so that the first connection layer 190 and the second connection layer 220 can be manufactured at the same time, and the productivity of the semiconductor light emitting device 1 can be improved.
  • the first bonding pad electrode 200 formed on the first connection layer 190 and the second bonding pad electrode 230 formed on the second connection layer 220 have the same configuration. By doing so, the first bonding pad electrode 200 and the second bonding pad electrode 230 can be formed simultaneously, and the productivity of the semiconductor light emitting device 1 can be improved.
  • the inventor manufactures the semiconductor light emitting device 1 shown in FIG. 1 by combining various manufacturing conditions, and a known tape for the adhesion between the transparent electrode 170 and the first bonding pad electrode 200 in the first electrode 210.
  • the examination was performed based on a peel test (tape test).
  • the adhesion between the transparent electrode 170 and the first bonding pad electrode 200 includes the adhesion between the transparent electrode 170 and the first bonding layer 190 and the adhesion between the first bonding layer 190 and the first bonding pad electrode 200.
  • Adhesion with the first barrier layer 200a has a great influence.
  • FIG. 4 shows the relationship between various manufacturing conditions in Examples 1 to 15 and Comparative Examples 1 to 6 and the respective evaluation results.
  • the sputtering target material bonding layer metal
  • the presence or absence of oxygen plasma treatment on the transparent electrode 170 annealing
  • an IZO film was used as the transparent electrode 170.
  • the adhesion between the transparent electrode 170 and the first bonding pad electrode 200 in the first electrode 210 is shown in four ranks A to D.
  • the evaluation “A” means “good”, the evaluation [B] means slightly good, the evaluation “C” means “slightly bad”, and the evaluation “D” means “bad”.
  • Examples 1 to 5 and Comparative Examples 1 and 2 a Ta target was used as a sputtering target material for forming the first bonding layer 190.
  • an Nb target was used as a sputtering target material for forming the first bonding layer 190.
  • a Ti target was used as a sputtering target material for forming the first bonding layer 190.
  • the first barrier layer 200a was made of Pt
  • the first bonding layer 200b was made of Au.
  • the evaluation of adhesion was A or B. That is, the adhesion between the transparent electrode 170 and the first bonding pad electrode 200 is improved depending on whether oxygen is introduced into the sputtering atmosphere in the bonding layer forming step or the oxygen plasma treatment is performed after the transparent electrode 170 is formed. Confirmed to do.
  • Examples 3, 8, and 13 in which the first bonding layer 190 was formed by sputtering in an oxygen atmosphere and then annealed, and in addition to this, oxygen plasma treatment of the transparent electrode 170 was performed.
  • the evaluation of adhesion was A.
  • FIG. 5 shows the result of analyzing the first electrode 210 in the semiconductor light emitting device 1 of Example 5 by depth analysis of X-ray photoelectron spectroscopy (XPS).
  • XPS X-ray photoelectron spectroscopy
  • the first barrier layer 200a is formed in the film. It can be seen that a large amount of Pt exists. It can also be seen that in the region where the sputtering time is 200 to 1200 sec, Ta and O constituting the first bonding layer 190 exist, that is, most of Ta exists in an oxidized state. Next, it can be understood that In, Zn, and O exist in the region where the sputtering time is 1200 to 3000 seconds, and that the Zn concentration is lower than In, that is, exists in an IZO state. That is, it is understood that an oxide of valve metal (here, Ta) can be formed by forming the first bonding layer 190 using the method described in this embodiment.
  • Ta an oxide of valve metal
  • FIG. 6 shows a TEM (Transmission Electron Microscope) photograph of the cross section of the first electrode 210 in the semiconductor light emitting device 1 of Example 4. However, only the transparent electrode 170 excluding the first bonding layer 200b, the first bonding layer 190, and the first barrier layer 200a of the first electrode 210 are shown here. In photographing, the incident direction of the electron beam was GaN [10 1 0].
  • FIG. 6 there is a Ta oxide layer on the IZO or transparent electrode 170 side between the transparent electrode 170 made of IZO and the first barrier layer 200a made of Pt, and Ta on the Pt or first barrier layer 200a side.
  • the first bonding layer 190 in which the metal layer exists is formed.
  • the oxide of the valve metal here, Ta
  • the first barrier layer 200a side is formed. It is understood that a valve metal can be formed.
  • the first bonding layer 190 is configured by the valve metal oxide. 190 has sufficient electrical conduction characteristics to be used as an electrode. This is because, in the first bonding layer 190, the oxidation of the valve metal, for example in the case of Ta is that not in the form of Ta 2 O 5, are present in the form of conductor Ta 2 O 5-x It is thought to be caused by
  • the inventor manufactures the semiconductor light emitting device 1 shown in FIG. 1 by combining various manufacturing conditions, examines the conduction state between the n contact layer 140a and the second bonding pad electrode 230, that is, ohmic characteristics, Further, the adhesion between the n-contact layer 140a and the second bonding pad electrode 230 was examined based on a known tape peeling test (tape test). Note that the adhesion between the n contact layer 140a and the second bonding pad electrode 230 includes the adhesion between the n contact layer 140a and the second bonding layer 220 and the second bonding layer 220 and the second bonding pad electrode. The adhesion between the second barrier layer 230a and the second barrier layer 230a is greatly affected.
  • FIG. 7 shows the relationship between the various production conditions in Examples 16 to 21 and Comparative Examples 7 to 9 and the respective evaluation results.
  • a sputtering target material bonding layer metal
  • whether oxygen is introduced into the atmosphere in sputtering, and whether nitrogen is introduced into the atmosphere in sputtering are shown. It is described.
  • evaluation items ohmic characteristics between the n contact layer 140a and the second bonding pad electrode 230 and adhesion between the n contact layer 140a and the second bonding pad electrode 230 are shown as A, B, Shown in rank C.
  • the evaluation “A” means “good”, the evaluation “B” means “slightly good”, and the evaluation “C” means “bad”.
  • Examples 16 and 19 and Comparative Example 7 a Ta target was used as a sputtering target material for forming the second bonding layer 220.
  • an Nb target was used as a sputtering target material for forming the second bonding layer 220.
  • a Ti target was used as a sputtering target material for forming the second bonding layer 220.
  • oxygen was introduced into the sputtering atmosphere
  • nitrogen was introduced into the sputtering atmosphere.
  • Comparative Examples 7 to 9 oxygen and nitrogen were not introduced into the sputtering atmosphere, and only Ar was used.
  • the second barrier layer 230a was made of Pt
  • the second bonding layer 230b was made of Au.
  • the adhesion evaluation was B or more. That is, it was confirmed that the adhesion between the n contact layer 140a and the second bonding pad electrode 230 is improved by introducing oxygen or nitrogen into the sputtering atmosphere in the bonding layer forming step.
  • the adhesion evaluation was A, and the ohmic characteristic evaluation was A.
  • the adhesiveness between the n-contact layer 140a and the second electrode 240 of the semiconductor light emitting device 1 is improved by forming the second bonding layer 220 from the valve metal oxide or nitride. Is done.
  • the second bonding layer 220 is made of valve metal oxide or nitride, and the second bonding layer 220 is used as an electrode. It has sufficient electric conduction characteristics. This is because, in the second bonding layer 220, the oxide of the valve metal exists not in the form of Ta 2 O 5 in the case of Ta, but in the form of a conductor of Ta 2 O 5-x . Alternatively, it is considered that the nitride of the valve metal exists due to the presence of TaN 1-x conductivity type in the case of Ta, for example.
  • the inventor manufactures the semiconductor light emitting device 1 shown in FIG. 1 by combining various manufacturing conditions, and the adhesiveness between the transparent electrode 170 and the first bonding pad electrode 200 in the first electrode 210 is a known tape. The examination was performed based on a peel test (tape test).
  • the adhesion between the transparent electrode 170 and the first bonding pad electrode 200 includes the adhesion between the transparent electrode 170 and the first bonding layer 190 and the adhesion between the first bonding layer 190 and the first bonding pad electrode 200. Adhesion with the first barrier layer 200a has a great influence.
  • FIGS. 8 to 10 show the relationship between various manufacturing conditions in Examples 22 to 44 and Comparative Examples 10 to 15 and evaluation results on adhesion.
  • FIGS. 8 to 10 show the manufacturing conditions as the sputtering target material in the bonding layer forming step, the ratio of nitrogen in argon in the sputtering atmosphere, that is, the N 2 concentration (volume%) obtained.
  • the thickness ( ⁇ ) of one bonding layer 190 is described.
  • 8 to 10 show, as evaluation items, the adhesion between the transparent electrode 170 and the first bonding pad electrode 200 in the first electrode 210 in three ranks A to C.
  • the evaluation “A” means “good”, the evaluation “B” means “slightly good”, and the evaluation “C” means “bad”.
  • FIG. 8 shows examples (Examples 22 to 32) and comparative examples (Comparative Examples 10 and 11) when Ta is used as a target material.
  • FIG. 9 shows Examples (Examples 33 to 38) and Comparative Examples (Comparative Examples 12 and 13) when W is used as a target material.
  • FIG. 10 shows Examples (Examples 39 to 44) and Comparative Examples (Comparative Examples 14 and 15) when Ti is used as a target material.
  • an IZO film was used as the transparent electrode 170
  • the first barrier layer 200a was 1000 angstroms in Pt
  • the first bonding layer 200b was 5000 angstroms in Au. Produced. *
  • the adhesion evaluation in Examples 22 to 32 was A or B.
  • the N 2 concentration in the sputtering atmosphere is set to 20% by volume or more, thereby improving the adhesion.
  • the adhesion evaluation was C.
  • the adhesiveness was evaluated as A by setting the thickness of the first bonding layer 190 to 250 angstroms or more. It became. The inventor tried to form the first bonding layer 190 by sputtering under the condition that the N 2 concentration in the sputtering atmosphere was more than 50% by volume when Ta was used as the target material. The film formation rate decreased, and it was not practical in production.
  • the adhesion evaluation in Examples 33 to 38 was A or B.
  • the adhesion evaluation is A by setting the N 2 concentration in the sputtering atmosphere to 10 vol% or more. I understood it.
  • Comparative Examples 12 and 13 in which the N 2 concentration in the sputtering atmosphere was 0% by volume or 1.0% by volume the evaluation of adhesion was C.
  • the inventor tried to form the first bonding layer 190 by sputtering under the condition that the N 2 concentration in the sputtering atmosphere was more than 50% by volume when W was used as the target material. The film formation rate decreased, and it was not practical in production.
  • the adhesion evaluation in Examples 39 to 44 was A or B.
  • the adhesion evaluation is A by setting the N 2 concentration in the sputtering atmosphere to 10% by volume or more. I understood it.
  • the adhesion evaluation was C. Note that the present inventor tried to form the first bonding layer 190 by sputtering under the condition that the N 2 concentration in the sputtering atmosphere was more than 50% by volume when Ti was used as the target material. The film formation rate decreased, and it was not practical in production.
  • FIG. 11 illustrates an example of a result of the tape peeling test in the case where the first bonding layer 190 is formed by using Ta as a target material, having a constant thickness, and varying the N 2 concentration in the sputtering atmosphere. It is a figure for doing. Note that, here, the intermediate layer 120, the base layer 130, the n-type semiconductor layer 140, the light-emitting layer 150, the p-type semiconductor layer 160, the transparent electrode 170, and the first junction are formed on almost the entire surface of one wafer-like substrate 110.
  • the layer 190 and the first bonding pad electrode 200 (the first barrier layer 200a and the first bonding layer 200b) formed thereon are used as targets for the tape peeling test.
  • the thickness of the first bonding layer 190 is 100 angstroms
  • the thickness of the first barrier layer 200a made of Pt is 1000 angstroms
  • the thickness of the first bonding layer 200b made of Au is 5000 angstroms. .
  • FIG. 11A shows the result when the N 2 concentration in the sputtering atmosphere is 0% by volume (Comparative Example 10), and FIG. 11B shows the N 2 concentration in the sputtering atmosphere is 10% by volume.
  • FIG. 11 (c) shows the results when the N 2 concentration in the sputtering atmosphere is 15% by volume (not shown in the examples and comparative examples).
  • FIG. 11E shows the result when the N 2 concentration in the sputtering atmosphere is 25% by volume (Example, comparison).
  • FIG. 11 (f) shows the results when the N 2 concentration in the sputtering atmosphere is 30% by volume (not shown in the examples and comparative examples).
  • the N 2 concentration in the sputtering atmosphere is set to 15% by volume or more, more preferably 20% by volume or more, so that the transparent electrode 170 and the first bonding pad electrode 200 are in close contact with each other through the first bonding layer 190. It is understood that the film is improved and the film is hardly peeled off.
  • Ta is used as the target material, and the N 2 concentration in the sputtering atmosphere is kept constant at 7.5% by volume (except for FIG. 12A described later), and the thickness is varied.
  • the intermediate layer 120, the base layer 130, the n-type semiconductor layer 140, the light emitting layer 150, the p-type semiconductor layer 160, and the transparent electrode are formed on almost the entire surface of one wafer-like substrate 110.
  • the thickness of the first bonding layer 190 is 20 to 1000 angstroms
  • the thickness of the first barrier layer 200a made of Pt is 1000 angstroms
  • the thickness of the first bonding layer 200b made of Au is 5000 angstroms. It was.
  • the N 2 concentration in the sputtering atmosphere is set to 0% by volume, so that the first bonding layer 190 is formed of Ta which is not nitrided, and the thickness thereof is 20 ⁇ .
  • FIG. 12B shows the result of the case (not described in Examples and Comparative Examples).
  • FIG. 12B shows the case where the first bonding layer 190 is formed in a nitrogen atmosphere and its thickness is 20 angstroms (Example 24).
  • FIG. 12C shows the results when the first bonding layer 190 is formed in a nitrogen atmosphere and the thickness thereof is 100 angstroms (Example 25), and FIG.
  • FIG. 26 When the first bonding layer 190 is formed under a nitrogen atmosphere and the thickness thereof is 250 angstroms (Example 26), FIG.
  • FIG. 12E shows the first bonding layer 190 formed under a nitrogen atmosphere. Its thickness is 400
  • FIG. 12 (f) shows the results when the first bonding layer 190 is formed in a nitrogen atmosphere and the thickness is 700 ⁇ (Example 28).
  • FIG. 12G shows the results when the first bonding layer 190 is formed in a nitrogen atmosphere and the thickness thereof is 1000 angstroms (Example 29).
  • FIG. 13 shows X-ray photoelectron spectroscopy (XPS) of the first electrode 210 in the semiconductor light emitting device 1 corresponding to Example 23 (target material: Ta, N 2 concentration in sputtering atmosphere: 5.0% by volume).
  • X-ray Photoelectron Spectroscopy shows the result of analysis by depth analysis.
  • a sample for analysis was obtained by laminating the first bonding layer 190 on the transparent electrode 170 and laminating the first barrier layer 200a on the first bonding layer 190.
  • the thickness of the first bonding layer 190 is set to 400 ⁇ instead of 100 ⁇ .
  • the horizontal axis represents the sputtering time using Ar gas
  • the vertical axis represents the atomic concentration of each element. Note that the sputtering time corresponds to the position of the first electrode 210 in the depth direction.
  • the first barrier layer 200a is formed in the film. It can be seen that a large amount of Pt exists. In addition, in the region where the sputtering time is 200 to 600 seconds, it can be seen that a large amount of Ta and N constituting the first bonding layer 190 exist, that is, a part of Ta exists in a nitrided state. . In this analysis result, the concentration of the nitrogen element in the first bonding layer 190 is at a level that is a little less than 5% at the maximum. Next, it can be seen that In, Zn, and O exist in the region where the sputtering time is 600 to 1500 seconds, and that the Zn concentration is lower than In, that is, exists in an IZO state.
  • FIG. 14 shows the XPS depth analysis of the first electrode 210 in the semiconductor light emitting device 1 corresponding to Example 30 (target material: Ta, N 2 concentration in sputtering atmosphere: 10% by volume). Results are shown. However, as described above, a sample for analysis was obtained by laminating the first bonding layer 190 on the transparent electrode 170 and laminating the first barrier layer 200a on the first bonding layer 190. In this example, the thickness of the first bonding layer 190 is set to 400 ⁇ instead of 100 ⁇ . Note that the horizontal and vertical axes in FIG. 14 are the same as those described in FIG.
  • the first barrier layer 200a is formed in the film. It can be seen that a large amount of Pt exists. In addition, in the region where the sputtering time is 200 to 600 seconds, it can be seen that a large amount of Ta and N constituting the first bonding layer 190 exist, that is, a part of Ta exists in a nitrided state. . In this analysis result, the concentration of the nitrogen element in the first bonding layer 190 is at a level exceeding 5% at the maximum. Next, it can be seen that In, Zn, and O exist in the region where the sputtering time is 600 to 1500 seconds, and that the Zn concentration is lower than In, that is, exists in an IZO state.
  • FIG. 15 shows the XPS depth analysis of the first electrode 210 in the semiconductor light emitting device 1 corresponding to Example 32 (target material: Ta, N 2 concentration in sputtering atmosphere: 50% by volume). Results are shown. However, as described above, a sample for analysis was obtained by laminating the first bonding layer 190 on the transparent electrode 170 and laminating the first barrier layer 200a on the first bonding layer 190. In this example, the thickness of the first bonding layer 190 is set to 400 ⁇ instead of 100 ⁇ . Note that the horizontal and vertical axes in FIG. 15 are the same as those described in FIG.
  • the first barrier layer 200a is formed in the film. It can be seen that a large amount of Pt exists. In addition, in the region where the sputtering time is 200 to 600 seconds, it can be seen that a large amount of Ta and N constituting the first bonding layer 190 exist, that is, a part of Ta exists in a nitrided state. . In this analysis result, the concentration of the nitrogen element in the first bonding layer 190 is at a level exceeding 15% at the maximum. Next, it can be seen that In, Zn, and O exist in the region where the sputtering time is 600 to 1500 seconds, and that the Zn concentration is lower than In, that is, exists in an IZO state.
  • FIG. 16 analyzed the first electrode 210 in the semiconductor light emitting device 1 corresponding to Comparative Example 10 (target material: Ta, N 2 concentration in sputtering atmosphere: 0% by volume) by XPS depth analysis. Results are shown.
  • a sample for analysis was obtained by laminating the first bonding layer 190 on the transparent electrode 170 and laminating the first barrier layer 200a on the first bonding layer 190.
  • the thickness of the first bonding layer 190 is set to 400 ⁇ instead of 100 ⁇ . Note that the horizontal and vertical axes in FIG. 10 are the same as those described in FIG.
  • the first barrier layer 200a is formed in the film. It can be seen that a large amount of Pt exists. Further, it can be seen that in the region where the sputtering time is 200 to 600 seconds, a large amount of Ta constituting the first bonding layer 190 exists, that is, Ta exists in a state where it is not nitrided. Next, it can be seen that In, Zn, and O exist in the region where the sputtering time is 600 to 1500 seconds, and that the Zn concentration is lower than In, that is, exists in an IZO state.
  • the valve metal is formed by forming the first bonding layer 190 by the method described in this embodiment, more specifically, by performing sputtering in a nitrogen atmosphere.
  • a nitride of (here Ta) can be deposited. 13 to 16, the higher the N 2 concentration in the sputtering atmosphere when forming the first bonding layer 190, the sharper the peak shapes of Ta and N, that is, Ta becomes the transparent electrode 170. It is understood that it is difficult to diffuse to the side. When a large number of Ta diffuses to the transparent electrode 170 side, there is a possibility that the invaded Ta decomposes IZO constituting the transparent electrode 170 and precipitates In.
  • the adhesion between the transparent electrode 170 and the first bonding layer 190 is lowered, and as a result, the first bonding pad electrode 200 is easily peeled off. Therefore, by adopting a configuration including a valve metal nitride as the first bonding layer 190, the adhesion between the transparent electrode 170 and the first bonding pad electrode 200 via the first bonding layer 190 is increased. It will be understood that peeling is less likely to occur.
  • the first bonding layer 190 is formed of a nitride of valve metal, but the first bonding layer 190 is sufficient for use as an electrode. It has excellent electrical conduction characteristics. This is because, in the first bonding layer 190, a nitride of valve metal, for example those in the case of Ta is due to the relatively low resistivity of TaN, form rather than in the form of TaN TaN 1-x It can be considered that the first bonding layer 190 is formed in a state where Ta and TaN are mixed.
  • DESCRIPTION OF SYMBOLS 1 Semiconductor light-emitting device, 100 ... Laminated semiconductor layer, 110 ... Substrate, 120 ... Intermediate layer, 130 ... Underlayer, 140 ... N-type semiconductor layer, 140a ... n contact layer, 140b ... N clad layer, 140c ... Semiconductor layer exposure 150, light emitting layer, 150a, barrier layer, 150b, well layer, 160, p-type semiconductor layer, 160a, p-clad layer, 160b, p-contact layer, 160c, upper surface, 170, transparent electrode, 180, protective layer, DESCRIPTION OF SYMBOLS 190 ... 1st joining layer, 200 ... 1st bonding pad electrode, 200a ...

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Abstract

A semiconductor light emission element (1) includes: a substrate (110); a layered semiconductor layer (100) having a light emission layer (150) and layered on the substrate (110); a transparent electrode (170) containing an indium oxide and layered on the layered semiconductor layer (100); a first bonding layer (190) containing tantalum as a valve metal and layered on the transparent electrode (170) in such a manner that a tantalum nitride layer or a tantalum oxide layer is in contact with the transparent electrode (170); and a first bonding pad electrode (200) layered on the first bonding layer (190) and used for electrical connection with outside.  This improves the bonding property of the transparent electrode or the semiconductor layer with the connection electrode and the reliability of the electrode.

Description

半導体発光素子Semiconductor light emitting device
　本発明は、半導体発光素子に関するものである。 The present invention relates to a semiconductor light emitting device.
　近年、短波長光発光素子用の半導体材料として、ＧａＮ系化合物半導体が注目を集めている。ＧａＮ系化合物半導体は、サファイア単結晶を始めとして、種々の酸化物やＩＩＩ－Ｖ族化合物を基板として、その上に有機金属気相化学反応法（ＭＯＣＶＤ法）や分子線エピタキシー法（ＭＢＥ法）等によって形成される。 In recent years, GaN-based compound semiconductors have attracted attention as semiconductor materials for short wavelength light emitting devices. GaN-based compound semiconductors include sapphire single crystals, various oxides and III-V compounds as substrates, and metalorganic vapor phase chemical reaction method (MOCVD method) and molecular beam epitaxy method (MBE method). And so on.
　このようなＧａＮ系化合物半導体を用いた半導体発光素子では、通常、基板上に、ｎ型半導体層、発光層、ｐ型半導体層からなるＬＥＤ構造を有する積層半導体層を形成し、最上部のｐ型半導体層に透明電極およびボンディング用のパッド電極を形成する一方、ｐ型半導体層および発光層の一部をエッチング等によって除去して露出させたｎ型半導体層にボンディング用のパッド電極を形成する。 In such a semiconductor light emitting device using a GaN-based compound semiconductor, a stacked semiconductor layer having an LED structure composed of an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer is usually formed on a substrate, and the uppermost p A transparent electrode and a bonding pad electrode are formed on the p-type semiconductor layer, and a bonding pad electrode is formed on the n-type semiconductor layer exposed by removing a part of the p-type semiconductor layer and the light emitting layer by etching or the like. .
　公報記載の従来技術として、ＩＴＯ等の金属酸化物からなる透明電極上の一部領域に、ある程度の厚みを持ったボンディング用のパッド電極（接続電極）を配置する構成が知られている（特許文献１参照）。また、この特許文献１には、透明電極上のパッド電極をＡｕ／Ｃｒで構成すること、および、ｎ型窒化物半導体層上のパッド電極をＡｕ／Ｃｒで構成することが記載されている。 As a prior art described in the publication, there is known a configuration in which a bonding pad electrode (connection electrode) having a certain thickness is arranged in a partial region on a transparent electrode made of a metal oxide such as ITO (patent) Reference 1). Patent Document 1 describes that the pad electrode on the transparent electrode is made of Au / Cr, and that the pad electrode on the n-type nitride semiconductor layer is made of Au / Cr.
特開２００８－２４４５０３号公報JP 2008-244503 A
　ＣｒはＧａＮ等のＩＩＩ族窒化物半導体やＩＴＯ（Indium Tin Oxide）等の透明電極との接合性が高いことから、透明電極あるいは半導体層とパッド電極とを接合する接合層の構成材として用いることが考えられる。
　しかしながら、接合層にＣｒを用いた場合には、使用環境によっては接合層に外部から空気または水分が侵入しやすくなり、接合層へ侵入した空気または水分が、通電時に接合層を分解して、半導体発光素子の素子寿命を短くする恐れがあった。 Since Cr has high bondability with Group III nitride semiconductors such as GaN and transparent electrodes such as ITO (Indium Tin Oxide), it should be used as a component for the bonding layer that bonds the transparent electrode or semiconductor layer to the pad electrode. Can be considered.
However, when Cr is used for the bonding layer, depending on the use environment, air or moisture easily enters the bonding layer from the outside, and the air or moisture that has entered the bonding layer decomposes the bonding layer when energized, There is a risk of shortening the device life of the semiconductor light emitting device.
　本発明は、透明電極あるいは半導体層と接続電極との接合性および電極の信頼性を向上させることを目的とする。 An object of the present invention is to improve the bondability between a transparent electrode or a semiconductor layer and a connection electrode and the reliability of the electrode.
　本発明が適用される半導体発光素子は、基板と、発光層を含み基板上に積層される積層半導体層と、インジウム酸化物を含み積層半導体層上に積層される透明電極と、弁作用金属より選ばれた少なくとも一種の元素を含むとともに透明電極と接する側が元素の酸化物または窒化物の少なくともいずれか一方を含むように透明電極上に積層される接合層と、接合層上に積層されて外部との電気的な接続に用いられる接続電極とを含んでいる。 A semiconductor light emitting device to which the present invention is applied includes a substrate, a laminated semiconductor layer including a light emitting layer and stacked on the substrate, a transparent electrode including indium oxide and stacked on the stacked semiconductor layer, and a valve action metal. A bonding layer that is stacked on the transparent electrode so that the side in contact with the transparent electrode includes at least one of the selected element and at least one of an oxide or a nitride of the element; And a connection electrode used for electrical connection.
　このような半導体発光素子において、接合層が、Ａｌ、Ｔｉ、Ｚｎ、Ｚｒ、Ｎｂ、Ｗ、Ｍｇ、Ｂｉ、Ｓｉ、Ｈｆ、Ｔａからなる群より選ばれた少なくとも一種の元素を含んでいることを特徴とすることができる。
　また、接合層が元素の窒化物を含む場合に、接合層が、Ｔａ、Ｗ、Ｔｉからなる群より選ばれた少なくとも一種の元素を含んでいることを特徴とすることができる。
　また、接合層が元素の酸化物を含む場合に、接合層が、Ｔａ、Ｎｂ、Ｔｉからなる群より選ばれた少なくとも一種の元素を含んでいることを特徴とすることができる。
　さらに、接続電極が、Ａｕ、Ａｌまたはこれらの金属のいずれかを含む合金からなるボンディング層を有していることを特徴とすることができる。
　また、接続電極が、接合層とボンディング層との間に積層されるバリア層をさらに備え、バリア層が、Ａｇ、Ａｌ、Ｒｕ、Ｒｈ、Ｐｄ、Ｏｓ、Ｉｒ、Ｐｔ、Ｔｉ、Ｗ、Ｍｏ、Ｎｉ、Ｃｏ、Ｚｒ、Ｈｆ、Ｔａ、Ｎｂのうちの何れかまたはこれら金属の何れかを含む合金からなるものであることを特徴とすることができる。
　さらに、透明電極が、インジウム酸化物および亜鉛酸化物を含んで構成されることを特徴とすることができる。
　そして、積層半導体層が、ＩＩＩ族窒化物半導体にて構成されていることを特徴とすることができる。 In such a semiconductor light emitting device, the bonding layer contains at least one element selected from the group consisting of Al, Ti, Zn, Zr, Nb, W, Mg, Bi, Si, Hf, and Ta. Can be a feature.
In addition, when the bonding layer includes an element nitride, the bonding layer may include at least one element selected from the group consisting of Ta, W, and Ti.
Further, when the bonding layer includes an oxide of an element, the bonding layer may include at least one element selected from the group consisting of Ta, Nb, and Ti.
Furthermore, the connection electrode may have a bonding layer made of Au, Al, or an alloy containing any of these metals.
The connection electrode further includes a barrier layer stacked between the bonding layer and the bonding layer, and the barrier layer includes Ag, Al, Ru, Rh, Pd, Os, Ir, Pt, Ti, W, Mo, It can be characterized by being made of an alloy containing any one of Ni, Co, Zr, Hf, Ta, Nb or any of these metals.
Furthermore, the transparent electrode can be characterized by comprising indium oxide and zinc oxide.
The laminated semiconductor layer may be formed of a group III nitride semiconductor.
　また、他の観点から捉えると、本発明が適用される半導体発光素子は、基板と、発光層を有するＩＩＩ族窒化物半導体にて構成され基板上に積層される積層半導体層と、弁作用金属より選ばれた少なくとも一種の元素を含むとともに積層半導体層のうちの一つの半導体層と接する側が元素の酸化物または窒化物の少なくともいずれか一方を含むように一つの半導体層上に積層される接合層と、接合層上に積層されて外部との電気的な接続に用いられる接続電極とを含んでいる。 From another point of view, a semiconductor light emitting device to which the present invention is applied includes a substrate, a laminated semiconductor layer formed of a group III nitride semiconductor having a light emitting layer and stacked on the substrate, and a valve metal Junction laminated on one semiconductor layer so as to contain at least one element selected from the above and the side in contact with one semiconductor layer of the laminated semiconductor layers contains at least one of an oxide or nitride of the element And a connection electrode stacked on the bonding layer and used for electrical connection with the outside.
　このような半導体発光素子において、接合層が、Ａｌ、Ｔｉ、Ｚｎ、Ｚｒ、Ｎｂ、Ｍｇ、Ｂｉ、Ｓｉ、Ｈｆ、Ｔａからなる群より選ばれた少なくとも一種の元素を含んでいることを特徴とすることができる。
　また、接合層が、Ｔａ、Ｎｂ、Ｔｉからなる群より選ばれた少なくとも一種の元素を含んでいることを特徴とすることができる。
　さらに、接続電極が、Ａｕ、Ａｌまたはこれらの金属のいずれかを含む合金からなるボンディング層を有していることを特徴とすることができる。
　また、接続電極が、接合層とボンディング層との間に積層されるバリア層をさらに備え、バリア層が、Ａｇ、Ａｌ、Ｒｕ、Ｒｈ、Ｐｄ、Ｏｓ、Ｉｒ、Ｐｔ、Ｔｉ、Ｗ、Ｍｏ、Ｎｉ、Ｃｏ、Ｚｒ、Ｈｆ、Ｔａ、Ｎｂのうちの何れかまたはこれら金属の何れかを含む合金からなるものであることを特徴とすることができる。 In such a semiconductor light emitting device, the bonding layer includes at least one element selected from the group consisting of Al, Ti, Zn, Zr, Nb, Mg, Bi, Si, Hf, and Ta. can do.
The bonding layer may include at least one element selected from the group consisting of Ta, Nb, and Ti.
Furthermore, the connection electrode may have a bonding layer made of Au, Al, or an alloy containing any of these metals.
The connection electrode further includes a barrier layer stacked between the bonding layer and the bonding layer, and the barrier layer includes Ag, Al, Ru, Rh, Pd, Os, Ir, Pt, Ti, W, Mo, It can be characterized by being made of an alloy containing any one of Ni, Co, Zr, Hf, Ta, Nb or any of these metals.
　さらに、他の観点から捉えると、本発明が適用される半導体発光素子は、第１の導電型を有する第１の半導体層と、第１の半導体層の上に積層される発光層と、発光層の上に積層され、第１の導電型とは逆の第２の導電型を有する第２の半導体層と、第２の半導体層の上に積層され、インジウム酸化物を含むとともに発光層から出力される光に対し透光性を有する透明電極と、弁作用金属より選ばれた少なくとも一種の元素を含むとともに透明電極と接する側が元素の酸化物または窒化物の少なくともいずれか一方を含むように透明電極上に積層される第１の接合層と、第１の接合層上に積層されて外部との電気的な接続に用いられる第１の接続電極と、弁作用金属より選ばれた少なくとも一種の元素を含むとともに第１の半導体層と接する側が元素の酸化物または窒化物の少なくともいずれか一方を含むように第１の半導体層上に積層される第２の接合層と、第２の接合層上に積層されて外部との電気的な接続に用いられる第２の接続電極とを有している。 Further, from another viewpoint, a semiconductor light emitting element to which the present invention is applied includes a first semiconductor layer having a first conductivity type, a light emitting layer stacked on the first semiconductor layer, and light emission. A second semiconductor layer having a second conductivity type opposite to the first conductivity type; and a second semiconductor layer stacked on the second semiconductor layer, including indium oxide and from the light emitting layer. A transparent electrode having translucency with respect to the output light and at least one element selected from valve action metals and a side in contact with the transparent electrode include at least one of an oxide or a nitride of the element At least one selected from a first bonding layer stacked on the transparent electrode, a first connection electrode stacked on the first bonding layer and used for electrical connection to the outside, and a valve metal In contact with the first semiconductor layer A second bonding layer that is stacked on the first semiconductor layer so that the side includes at least one of an oxide or a nitride of the element, and an electrical interface between the second bonding layer and the second bonding layer that is stacked on the second bonding layer And a second connection electrode used for connection.
　このような半導体発光素子において、第１の半導体層は電子をキャリアとするｎ型半導体層からなり、第２の半導体層は正孔をキャリアとするｐ型半導体層からなることを特徴とすることができる。
　また、第１の接合層および第２の接合層が、Ａｌ、Ｔｉ、Ｚｎ、Ｚｒ、Ｎｂ、Ｗ、Ｍｇ、Ｂｉ、Ｓｉ、Ｈｆ、Ｔａからなる群より選ばれた少なくとも一種の元素を含んでいることを特徴とすることができる。
　さらに、第１の接合層および第２の接合層が、同じ元素の酸化物または窒化物を含んで構成されることを特徴とすることができる。
　また、第１の接続電極および第２の接続電極が、同じ金属または同じ合金を含んで構成されることを特徴とすることができる。
　さらに、透明電極が、インジウム酸化物および亜鉛酸化物を含んで構成されることを特徴とすることができる。
　そして、第１の半導体層、発光層および第２の半導体層が、ＩＩＩ族窒化物半導体にて構成されていることを特徴とすることができる。 In such a semiconductor light emitting device, the first semiconductor layer is composed of an n-type semiconductor layer having electrons as carriers, and the second semiconductor layer is composed of a p-type semiconductor layer having holes as carriers. Can do.
Further, the first bonding layer and the second bonding layer contain at least one element selected from the group consisting of Al, Ti, Zn, Zr, Nb, W, Mg, Bi, Si, Hf, and Ta. It can be characterized by being.
Furthermore, the first bonding layer and the second bonding layer can be characterized by including an oxide or nitride of the same element.
Further, the first connection electrode and the second connection electrode may be configured to include the same metal or the same alloy.
Furthermore, the transparent electrode can be characterized by comprising indium oxide and zinc oxide.
The first semiconductor layer, the light emitting layer, and the second semiconductor layer may be made of a group III nitride semiconductor.
本発明によれば、透明電極あるいは半導体層と接続電極との接合性および電極の信頼性を向上させることができる。 ADVANTAGE OF THE INVENTION According to this invention, the adhesiveness of a transparent electrode or a semiconductor layer, and a connection electrode and the reliability of an electrode can be improved.
半導体発光素子の断面模式図の一例である。It is an example of the cross-sectional schematic diagram of a semiconductor light-emitting device. 半導体発光素子の平面模式図の一例である。It is an example of the plane schematic diagram of a semiconductor light-emitting device. 半導体発光素子を構成する積層半導体層の断面模式図の一例である。It is an example of the cross-sectional schematic diagram of the laminated semiconductor layer which comprises a semiconductor light-emitting device. 第１の実施例の、各実施例および各比較例における半導体発光素子の製造条件および評価結果を示す図である。It is a figure which shows the manufacturing conditions and evaluation result of a semiconductor light-emitting device in each Example and each comparative example of a 1st Example. 実施例５の半導体発光素子における第１の電極を、Ｘ線光電子分光法（ＸＰＳ：X-ray Photoelectron Spectroscopy）の深さ分析によって解析した結果を示す図である。It is a figure which shows the result of having analyzed the 1st electrode in the semiconductor light-emitting device of Example 5 by the depth analysis of X-ray photoelectron spectroscopy (XPS: X-ray | Photophoton | Spectroscopy). 実施例４の半導体発光素子における第１の電極の断面のＴＥＭ（Transmission Electron Microscope）写真である。10 is a TEM (Transmission Electron Microscope) photograph of a cross section of a first electrode in the semiconductor light emitting device of Example 4. 第２の実施例の、各実施例および各比較例における半導体発光素子の製造条件および評価結果を示す図である。It is a figure which shows the manufacturing conditions and evaluation result of the semiconductor light-emitting element in each Example and each comparative example of a 2nd Example. 第３の実施例の、実施例２２～３２および比較例１０、１１における各種製造条件と、密着性に関する評価結果との関係を示す図である。It is a figure which shows the relationship between the various manufacture conditions in Examples 22-32 and Comparative Examples 10 and 11 of a 3rd Example, and the evaluation result regarding adhesiveness. 第３の実施例の、実施例３３～３８および比較例１２、１３における各種製造条件と、密着性に関する評価結果との関係を示す図である。It is a figure which shows the relationship between the various manufacture conditions in Examples 33-38 of Comparative Example 3, and Comparative Examples 12 and 13, and the evaluation result regarding adhesiveness. 第３の実施例の、実施例３９～４４および比較例１４、１５における各種製造条件と、密着性に関する評価結果との関係を示す図である。It is a figure which shows the relationship between the various manufacture conditions in Examples 39-44 and Comparative Examples 14 and 15 of a 3rd Example, and the evaluation result regarding adhesiveness. Ｔａをターゲット材とし、かつ、厚さを一定とし、スパッタ雰囲気中のＮ2濃度をそれぞれ異ならせて第１の接合層を形成した場合におけるテープ剥離試験の結果の一例を説明するための図である。In figure for the Ta as a target material, and the thickness is constant, an example of results of the tape peel test in the case of forming the first bonding layer with different N 2 concentration in the sputtering atmosphere, respectively is there. Ｔａをターゲット材とし、且つ、スパッタ雰囲気中のＮ2濃度を７．５体積％で一定とし、厚さをそれぞれ異ならせて第１の接合層を形成した場合におけるテープ剥離試験の結果の一例を説明するための図である。Example of tape peel test results when Ta is the target material, the N 2 concentration in the sputtering atmosphere is constant at 7.5% by volume, and the first bonding layer is formed with different thicknesses. It is a figure for demonstrating. 実施例２３に対応する半導体発光素子における第１の電極を、Ｘ線光電子分光法の深さ分析によって解析した結果を示す図である。It is a figure which shows the result of having analyzed the 1st electrode in the semiconductor light-emitting device corresponding to Example 23 by the depth analysis of a X ray photoelectron spectroscopy. 実施例３０に対応する半導体発光素子における第１の電極を、Ｘ線光電子分光法の深さ分析によって解析した結果を示す図である。It is a figure which shows the result of having analyzed the 1st electrode in the semiconductor light-emitting device corresponding to Example 30 by the depth analysis of a X ray photoelectron spectroscopy. 実施例３２に対応する半導体発光素子における第１の電極を、Ｘ線光電子分光法の深さ分析によって解析した結果を示す図である。It is a figure which shows the result of having analyzed the 1st electrode in the semiconductor light-emitting device corresponding to Example 32 by the depth analysis of a X ray photoelectron spectroscopy. 比較例１０に対応する半導体発光素子における第１の電極を、Ｘ線光電子分光法の深さ分析によって解析した結果を示す図である。It is a figure which shows the result of having analyzed the 1st electrode in the semiconductor light-emitting device corresponding to the comparative example 10 by the depth analysis of a X ray photoelectron spectroscopy.
　以下、添付図面を参照して、本発明の実施の形態について詳細に説明する。
　図１は本実施の形態が適用される半導体発光素子（発光ダイオード）１の断面模式図の一例を示しており、図２は図１に示す半導体発光素子１の平面模式図の一例を示しており、図３は半導体発光素子を構成する積層半導体層の断面模式図の一例を示している。 Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 shows an example of a schematic cross-sectional view of a semiconductor light emitting device (light emitting diode) 1 to which the present embodiment is applied, and FIG. 2 shows an example of a schematic plan view of the semiconductor light emitting device 1 shown in FIG. FIG. 3 shows an example of a schematic cross-sectional view of the laminated semiconductor layer constituting the semiconductor light emitting element.
（半導体発光素子）
　図１に示すように、半導体発光素子１は、基板１１０と、基板１１０上に積層される中間層１２０と、中間層１２０上に積層される下地層１３０とを備える。また、半導体発光素子１は、下地層１３０上に積層されるｎ型半導体層１４０と、ｎ型半導体層１４０上に積層される発光層１５０と、発光層１５０上に積層されるｐ型半導体層１６０とを備える。なお、以下の説明においては、必要に応じて、これらｎ型半導体層１４０、発光層１５０およびｐ型半導体層１６０を、まとめて積層半導体層１００と呼ぶ。さらに、半導体発光素子１は、ｐ型半導体層１６０上に積層される透明電極１７０と、透明電極１７０上に積層される保護層１８０とを備える。そして、半導体発光素子１は、透明電極１７０のうち保護層１８０によって覆われない部位に積層される第１の接合層１９０と、第１の接合層１９０上に積層される第１のボンディングパッド電極２００とを備える。さらにまた、半導体発光素子１は、ｐ型半導体層１６０、発光層１５０およびｎ型半導体層１４０の一部を切り欠くことによって露出したｎ型半導体層１４０の半導体層露出面１４０ｃ上の一部に積層される第２の接合層２２０と、第２の接合層２２０上に積層される第２のボンディングパッド電極２３０とを備える。ここで、保護層１８０は、半導体層露出面１４０ｃ上にも形成されており、第２の接合層２２０は、半導体層露出面１４０ｃのうち保護層１８０によって覆われない部位に積層されている。なお、以下の説明においては、透明電極１７０と透明電極１７０上に積層される第１の接合層１９０と第１のボンディングパッド電極２００とを、まとめて第１の電極２１０と呼ぶ。また、以下の説明においては、第２の接合層２２０と第２のボンディングパッド電極２３０とを、まとめて第２の電極２４０と呼ぶ。
　この半導体発光素子１においては、第１の電極２１０における第１のボンディングパッド電極２００を正極、第２の電極２４０を負極とし、両者を介して被給電体の一例としての積層半導体１００（より具体的にはｐ型半導体層１６０、発光層１５０およびｎ型半導体層１４０）に電流を流すことで、発光層１５０が発光するようになっている。 (Semiconductor light emitting device)
As shown in FIG. 1, the semiconductor light emitting device 1 includes a substrate 110, an intermediate layer 120 stacked on the substrate 110, and a base layer 130 stacked on the intermediate layer 120. Further, the semiconductor light emitting device 1 includes an n-type semiconductor layer 140 stacked on the base layer 130, a light-emitting layer 150 stacked on the n-type semiconductor layer 140, and a p-type semiconductor layer stacked on the light-emitting layer 150. 160. In the following description, the n-type semiconductor layer 140, the light emitting layer 150, and the p-type semiconductor layer 160 are collectively referred to as a laminated semiconductor layer 100 as necessary. Further, the semiconductor light emitting device 1 includes a transparent electrode 170 stacked on the p-type semiconductor layer 160 and a protective layer 180 stacked on the transparent electrode 170. The semiconductor light emitting device 1 includes a first bonding layer 190 stacked on a portion of the transparent electrode 170 that is not covered by the protective layer 180, and a first bonding pad electrode stacked on the first bonding layer 190. 200. Furthermore, the semiconductor light emitting device 1 is formed on a part of the semiconductor layer exposed surface 140c of the n type semiconductor layer 140 exposed by cutting out a part of the p type semiconductor layer 160, the light emitting layer 150, and the n type semiconductor layer 140. A second bonding layer 220 to be stacked, and a second bonding pad electrode 230 to be stacked on the second bonding layer 220 are provided. Here, the protective layer 180 is also formed on the semiconductor layer exposed surface 140c, and the second bonding layer 220 is stacked on a portion of the semiconductor layer exposed surface 140c that is not covered by the protective layer 180. In the following description, the transparent electrode 170, the first bonding layer 190 stacked on the transparent electrode 170, and the first bonding pad electrode 200 are collectively referred to as a first electrode 210. In the following description, the second bonding layer 220 and the second bonding pad electrode 230 are collectively referred to as the second electrode 240.
In the semiconductor light emitting device 1, the first bonding pad electrode 200 in the first electrode 210 is a positive electrode and the second electrode 240 is a negative electrode, and a laminated semiconductor 100 as an example of a power-supplied body via both (more specifically, Specifically, the light emitting layer 150 emits light by passing a current through the p-type semiconductor layer 160, the light-emitting layer 150, and the n-type semiconductor layer 140).
　では次に、半導体発光素子１の各構成要素について、より詳細に説明する。
＜基板＞
　基板１１０としては、ＩＩＩ族窒化物半導体結晶が表面にエピタキシャル成長される基板であれば、特に限定されず、各種の基板を選択して用いることができる。例えば、サファイア、ＳｉＣ、シリコン、酸化亜鉛、酸化マグネシウム、酸化マンガン、酸化ジルコニウム、酸化マンガン亜鉛鉄、酸化マグネシウムアルミニウム、ホウ化ジルコニウム、酸化ガリウム、酸化インジウム、酸化リチウムガリウム、酸化リチウムアルミニウム、酸化ネオジウムガリウム、酸化ランタンストロンチウムアルミニウムタンタル、酸化ストロンチウムチタン、酸化チタン、ハフニウム、タングステン、モリブデン等からなる基板を用いることができる。
　また、上記基板の中でも、特に、ｃ面を主面とするサファイア基板を用いることが好ましい。サファイア基板を用いる場合は、サファイアのｃ面上に中間層１２０（バッファ層）を形成するとよい。 Next, each component of the semiconductor light emitting element 1 will be described in more detail.
<Board>
The substrate 110 is not particularly limited as long as a group III nitride semiconductor crystal is epitaxially grown on the surface, and various substrates can be selected and used. For example, sapphire, SiC, silicon, zinc oxide, magnesium oxide, manganese oxide, zirconium oxide, manganese zinc iron oxide, magnesium aluminum oxide, zirconium boride, gallium oxide, indium oxide, lithium gallium oxide, lithium aluminum oxide, neodymium gallium oxide A substrate made of lanthanum strontium oxide aluminum tantalum, strontium titanium oxide, titanium oxide, hafnium, tungsten, molybdenum, or the like can be used.
Further, among the above substrates, it is particularly preferable to use a sapphire substrate having a c-plane as a main surface. When a sapphire substrate is used, an intermediate layer 120 (buffer layer) is preferably formed on the c-plane of sapphire.
　なお、上記基板の内、高温でアンモニアに接触することで化学的な変性を引き起こすことが知られている酸化物基板や金属基板等を用いることができ、アンモニアを使用せずに中間層１２０を成膜することもでき、またアンモニアを使用する方法では、後述のｎ型半導体層１４０を構成するために下地層１３０を成膜した場合には、中間層１２０がコート層としても作用するので、これらの方法は基板１１０の化学的な変質を防ぐ点で効果的である。
　また、中間層１２０をスパッタ法により形成した場合、基板１１０の温度を低く抑えることが可能なので、高温で分解してしまう性質を持つ材料からなる基板１１０を用いた場合でも、基板１１０にダメージを与えることなく基板上への各層の成膜が可能である。 Of the above substrates, an oxide substrate or a metal substrate that is known to cause chemical modification by contact with ammonia at a high temperature can be used, and the intermediate layer 120 can be formed without using ammonia. In the method using ammonia, when the base layer 130 is formed to form the n-type semiconductor layer 140 described later, the intermediate layer 120 also functions as a coat layer. These methods are effective in preventing chemical alteration of the substrate 110.
Further, when the intermediate layer 120 is formed by a sputtering method, the temperature of the substrate 110 can be kept low, so that even when the substrate 110 made of a material that decomposes at a high temperature is used, the substrate 110 is damaged. Each layer can be formed on the substrate without giving.
＜積層半導体層＞
　積層半導体層１００は、例えば、ＩＩＩ族窒化物半導体からなる層であって、図１に示すように、基板１１０上に、ｎ型半導体層１４０、発光層１５０およびｐ型半導体層１６０の各層がこの順で積層されて構成されている。
　また、図３に示すように、ｎ型半導体層１４０、発光層１５０及びｐ型半導体層１６０の各層は、それぞれ、複数の半導体層から構成してもよい。さらにまた、積層半導体層１００は、さらに下地層１３０、中間層１２０を含めて呼んでもよい。ここで、ｎ型半導体層１４０は、電子をキャリアとする第１の導電型にて電気伝導を行い、ｐ型半導体層１６０は、正孔をキャリアとする第２の導電型にて電気伝導を行う。
　なお、積層半導体層１００は、ＭＯＣＶＤ法で形成すると結晶性の良いものが得られるが、スパッタ法によっても条件を最適化することで、ＭＯＣＶＤ法よりも優れた結晶性を有する半導体層を形成できる。以下、順次説明する。 <Laminated semiconductor layer>
The laminated semiconductor layer 100 is a layer made of, for example, a group III nitride semiconductor. As shown in FIG. 1, the n-type semiconductor layer 140, the light emitting layer 150, and the p-type semiconductor layer 160 are formed on the substrate 110. They are stacked in this order.
As shown in FIG. 3, each of the n-type semiconductor layer 140, the light emitting layer 150, and the p-type semiconductor layer 160 may be composed of a plurality of semiconductor layers. Furthermore, the laminated semiconductor layer 100 may further be referred to as including the base layer 130 and the intermediate layer 120. Here, the n-type semiconductor layer 140 conducts electricity in the first conductivity type using electrons as carriers, and the p-type semiconductor layer 160 conducts electricity in the second conductivity type using holes as carriers. Do.
Note that although the stacked semiconductor layer 100 can be formed with good crystallinity when formed by the MOCVD method, a semiconductor layer having crystallinity superior to that of the MOCVD method can be formed by optimizing the conditions also by the sputtering method. . Hereinafter, description will be made sequentially.
＜中間層＞
　中間層１２０は、多結晶のＡｌxＧａ1-xＮ（０≦ｘ≦１）からなるものが好ましく、単結晶のＡｌxＧａ1-xＮ（０≦ｘ≦１）のものがより好ましい。
　中間層１２０は、上述のように、例えば、多結晶のＡｌxＧａ1-xＮ（０≦ｘ≦１）からなる厚さ０．０１～０．５μｍのものとすることができる。中間層１２０の厚みが０．０１μｍ未満であると、中間層１２０により基板１１０と下地層１３０との格子定数の違いを緩和する効果が十分に得られない場合がある。また、中間層１２０の厚みが０．５μｍを超えると、中間層１２０としての機能には変化が無いのにも関わらず、中間層１２０の成膜処理時間が長くなり、生産性が低下する虞がある。
　中間層１２０は、基板１１０と下地層１３０との格子定数の違いを緩和し、基板１１０の（０００１）面（Ｃ面）上にＣ軸配向した単結晶層の形成を容易にする働きがある。したがって、中間層１２０の上に単結晶の下地層１３０を積層すると、より一層結晶性の良い下地層１３０が積層できる。なお、本発明においては、中間層形成工程を行なうことが好ましいが、行なわなくても良い。 <Intermediate layer>
The intermediate layer 120 is preferably made of polycrystalline Al x Ga 1-x N ( 0 ≦ x ≦ 1) , and more preferably those of the single crystal Al x Ga 1-x N ( 0 ≦ x ≦ 1) .
As described above, the intermediate layer 120 can be, for example, made of polycrystalline Al x Ga 1-x N (0 ≦ x ≦ 1) and having a thickness of 0.01 to 0.5 μm. If the thickness of the intermediate layer 120 is less than 0.01 μm, the intermediate layer 120 may not sufficiently obtain an effect of relaxing the difference in lattice constant between the substrate 110 and the base layer 130. In addition, when the thickness of the intermediate layer 120 exceeds 0.5 μm, the film forming process time of the intermediate layer 120 becomes long and the productivity may be lowered although the function as the intermediate layer 120 is not changed. There is.
The intermediate layer 120 has a function of reducing the difference in lattice constant between the substrate 110 and the base layer 130 and facilitating formation of a C-axis oriented single crystal layer on the (0001) plane (C plane) of the substrate 110. . Therefore, when the single crystal base layer 130 is stacked on the intermediate layer 120, the base layer 130 with higher crystallinity can be stacked. In the present invention, the intermediate layer forming step is preferably performed, but may not be performed.
　また、中間層１２０は、ＩＩＩ族窒化物半導体からなる六方晶系の結晶構造を持つものであってもよい。また、中間層１２０をなすＩＩＩ族窒化物半導体の結晶は、単結晶構造を有するものであってもよく、単結晶構造を有するものが好ましく用いられる。ＩＩＩ族窒化物半導体の結晶は、成長条件を制御することにより、上方向だけでなく、面内方向にも成長して単結晶構造を形成する。このため、中間層１２０の成膜条件を制御することにより、単結晶構造のＩＩＩ族窒化物半導体の結晶からなる中間層１２０とすることができる。このような単結晶構造を有する中間層１２０を基板１１０上に成膜した場合、中間層１２０のバッファ機能が有効に作用するため、その上に成膜されたＩＩＩ族窒化物半導体は良好な配向性及び結晶性を有する結晶膜となる。
　また、中間層１２０をなすＩＩＩ族窒化物半導体の結晶は、成膜条件をコントロールすることにより、六角柱を基本とした集合組織からなる柱状結晶（多結晶）とすることも可能である。なお、ここでの集合組織からなる柱状結晶とは、隣接する結晶粒との間に結晶粒界を形成して隔てられており、それ自体は縦断面形状として柱状になっている結晶のことをいう。 The intermediate layer 120 may have a hexagonal crystal structure made of a group III nitride semiconductor. Further, the group III nitride semiconductor crystal forming the intermediate layer 120 may have a single crystal structure, and preferably has a single crystal structure. By controlling the growth conditions, the group III nitride semiconductor crystal grows not only in the upward direction but also in the in-plane direction to form a single crystal structure. Therefore, by controlling the film forming conditions of the intermediate layer 120, the intermediate layer 120 made of a crystal of a group III nitride semiconductor having a single crystal structure can be obtained. When the intermediate layer 120 having such a single crystal structure is formed on the substrate 110, the buffer function of the intermediate layer 120 works effectively, so that the group III nitride semiconductor formed thereon has a good orientation. It becomes a crystal film having the property and crystallinity.
Further, the group III nitride semiconductor crystal forming the intermediate layer 120 can be formed into a columnar crystal (polycrystal) having a texture based on a hexagonal column by controlling the film forming conditions. In addition, the columnar crystal consisting of the texture here is a crystal that is separated by forming a crystal grain boundary between adjacent crystal grains, and is itself a columnar shape as a longitudinal sectional shape. Say.
＜下地層＞
　下地層１３０としては、ＡｌxＧａyＩｎzＮ（０≦ｘ≦１、０≦ｙ≦１、０≦ｚ≦１、ｘ＋ｙ＋ｚ＝１）を用いることができるが、ＡｌxＧａ1-xＮ（０≦ｘ＜１）を用いると結晶性の良い下地層１３０を形成できるため好ましい。
　下地層１３０の膜厚は０．１μｍ以上が好ましく、より好ましくは０．５μｍ以上であり、１μｍ以上が最も好ましい。この膜厚以上にした方が結晶性の良好なＡｌxＧａ1-xＮ層が得られやすい。
　下地層１３０の結晶性を良くするためには、下地層１３０は不純物をドーピングしない方が望ましい。しかし、ｐ型あるいはｎ型の導電性が必要な場合は、アクセプター不純物あるいはドナー不純物を添加することができる。 <Underlayer>
As the underlayer 130, Al x Ga y In z N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1, x + y + z = 1) can be used, but Al x Ga 1-x N It is preferable to use (0 ≦ x <1) because the base layer 130 with good crystallinity can be formed.
The film thickness of the underlayer 130 is preferably 0.1 μm or more, more preferably 0.5 μm or more, and most preferably 1 μm or more. An Al x Ga 1-x N layer with good crystallinity is more easily obtained when the thickness is increased.
In order to improve the crystallinity of the underlayer 130, it is desirable that the underlayer 130 is not doped with impurities. However, when p-type or n-type conductivity is required, acceptor impurities or donor impurities can be added.
＜ｎ型半導体層＞
　図３に示すように、第１の半導体層の一例としてのｎ型半導体層１４０は、ｎコンタクト層１４０ａとｎクラッド層１４０ｂとから構成されるのが好ましい。なお、ｎコンタクト層１４０ａはｎクラッド層１４０ｂを兼ねることも可能である。また、前述の下地層１３０をｎ型半導体層１４０に含めてもよい。
　ｎコンタクト層１４０ａは、第２の電極２４０を設けるための層である。ｎコンタクト層１４０ａとしては、ＡｌxＧａ1-xＮ層（０≦ｘ＜１、好ましくは０≦ｘ≦０．５、さらに好ましくは０≦ｘ≦０．１）から構成されることが好ましい。
　また、ｎコンタクト層１４０ａにはｎ型不純物がドープされていることが好ましく、ｎ型不純物を１×１０17～１×１０20／ｃｍ3、好ましくは１×１０18～１×１０19／ｃｍ3の濃度で含有すると、第２の電極２４０との良好なオーミック接触を維持できる点で好ましい。ｎ型不純物としては、特に限定されないが、例えば、Ｓｉ、ＧｅおよびＳｎ等が挙げられ、好ましくはＳｉおよびＧｅが挙げられる。
　ｎコンタクト層１４０ａの膜厚は、０．５～５μｍとされることが好ましく、１～３μｍの範囲に設定することがより好ましい。ｎコンタクト層１４０ａの膜厚が上記範囲にあると、半導体の結晶性が良好に維持される。 <N-type semiconductor layer>
As shown in FIG. 3, the n-type semiconductor layer 140 as an example of the first semiconductor layer is preferably composed of an n-contact layer 140a and an n-cladding layer 140b. The n contact layer 140a can also serve as the n clad layer 140b. In addition, the base layer 130 described above may be included in the n-type semiconductor layer 140.
The n contact layer 140 a is a layer for providing the second electrode 240. The n contact layer 140a is preferably composed of an Al x Ga 1-x N layer (0 ≦ x <1, preferably 0 ≦ x ≦ 0.5, more preferably 0 ≦ x ≦ 0.1). .
The n-contact layer 140a is preferably doped with an n-type impurity, and the n-type impurity is preferably 1 × 10 17 to 1 × 10 20 / cm 3 , preferably 1 × 10 18 to 1 × 10 19 / cm. When it is contained at a concentration of 3 , it is preferable in that good ohmic contact with the second electrode 240 can be maintained. Although it does not specifically limit as an n-type impurity, For example, Si, Ge, Sn, etc. are mentioned, Preferably Si and Ge are mentioned.
The thickness of the n contact layer 140a is preferably 0.5 to 5 μm, and more preferably set to a range of 1 to 3 μm. When the thickness of the n-contact layer 140a is in the above range, the crystallinity of the semiconductor is maintained well.
　ｎコンタクト層１４０ａと発光層１５０との間には、ｎクラッド層１４０ｂを設けることが好ましい。ｎクラッド層１４０ｂは、発光層１５０へのキャリアの注入とキャリアの閉じ込めとを行なう層である。ｎクラッド層１４０ｂはＡｌＧａＮ、ＧａＮ、ＧａＩｎＮなどで形成することが可能である。また、これらの構造のヘテロ接合や複数回積層した超格子構造としてもよい。ｎクラッド層１４０ｂをＧａＩｎＮで形成する場合には、発光層１５０のＧａＩｎＮのバンドギャップよりも大きくすることが望ましい。
　ｎクラッド層１４０ｂの膜厚は、特に限定されないが、好ましくは０．００５～０．５μｍであり、より好ましくは０．００５～０．１μｍである。ｎクラッド層１４０ｂのｎ型ドープ濃度は１×１０17～１×１０20／ｃｍ3が好ましく、より好ましくは１×１０18～１×１０19／ｃｍ3である。ドープ濃度がこの範囲であると、良好な結晶性の維持および素子の動作電圧低減の点で好ましい。 An n-clad layer 140b is preferably provided between the n-contact layer 140a and the light emitting layer 150. The n-cladding layer 140b is a layer that injects carriers into the light emitting layer 150 and confines carriers. The n-clad layer 140b can be formed of AlGaN, GaN, GaInN, or the like. Alternatively, a heterojunction of these structures or a superlattice structure in which a plurality of layers are stacked may be used. When the n-cladding layer 140b is formed of GaInN, it is desirable to make it larger than the band gap of GaInN of the light emitting layer 150.
The film thickness of the n-clad layer 140b is not particularly limited, but is preferably 0.005 to 0.5 μm, and more preferably 0.005 to 0.1 μm. The n-type doping concentration of the n-clad layer 140b is preferably 1 × 10 17 to 1 × 10 20 / cm 3 , more preferably 1 × 10 18 to 1 × 10 19 / cm 3 . A doping concentration within this range is preferable in terms of maintaining good crystallinity and reducing the operating voltage of the device.
　なお、ｎクラッド層１４０ｂを、超格子構造を含む層とする場合には、詳細な図示を省略するが、１００オングストローム以下の膜厚を有したＩＩＩ族窒化物半導体からなるｎ側第１層と、ｎ側第１層と組成が異なるとともに１００オングストローム以下の膜厚を有したＩＩＩ族窒化物半導体からなるｎ側第２層とが積層された構造を含むものであっても良い。
　また、ｎクラッド層１４０ｂは、ｎ側第１層とｎ側第２層とが交互に繰返し積層された構造を含んだものであってもよく、ＧａＩｎＮとＧａＮとの交互構造又は組成の異なるＧａＩｎＮ同士の交互構造であることが好ましい。 When the n-cladding layer 140b is a layer including a superlattice structure, a detailed illustration is omitted, but an n-side first layer made of a group III nitride semiconductor having a thickness of 100 angstroms or less and It may include a structure in which an n-side second layer made of a group III nitride semiconductor having a composition different from that of the n-side first layer and having a film thickness of 100 angstroms or less is stacked.
Further, the n-cladding layer 140b may include a structure in which n-side first layers and n-side second layers are alternately and repeatedly stacked. The GaInN and GaN alternate structures or GaInN having different compositions. It is preferable that they have an alternating structure.
＜発光層＞
　ｎ型半導体層１４０の上に積層される発光層１５０としては、単一量子井戸構造あるいは多重量子井戸構造などを採用することができる。
　図３に示すような、量子井戸構造の井戸層１５０ｂとしては、Ｇａ1-yＩｎyＮ（０＜ｙ＜０．４）からなるＩＩＩ族窒化物半導体層が通常用いられる。井戸層１５０ｂの膜厚としては、量子効果の得られる程度の膜厚、例えば１～１０ｎｍとすることができ、好ましくは２～６ｎｍとすると発光出力の点で好ましい。
　また、多重量子井戸構造の発光層１５０の場合は、上記Ｇａ1-yＩｎyＮを井戸層１５０ｂとし、井戸層１５０ｂよりバンドギャップエネルギーが大きいＡｌzＧａ1-zＮ（０≦ｚ＜０．３）を障壁層１５０ａとする。井戸層１５０ｂおよび障壁層１５０ａには、設計により不純物をドープしてもしなくてもよい。 <Light emitting layer>
As the light emitting layer 150 stacked on the n-type semiconductor layer 140, a single quantum well structure or a multiple quantum well structure can be employed.
As a well layer 150b having a quantum well structure as shown in FIG. 3, a group III nitride semiconductor layer made of Ga 1-y In y N (0 <y <0.4) is usually used. The film thickness of the well layer 150b can be set to a film thickness at which a quantum effect can be obtained, for example, 1 to 10 nm, and preferably 2 to 6 nm from the viewpoint of light emission output.
In the case of the light emitting layer 150 having a multiple quantum well structure, the Ga 1-y In y N is used as the well layer 150b, and Al z Ga 1-z N (0 ≦ z <0) having a larger band gap energy than the well layer 150b. .3) is defined as a barrier layer 150a. The well layer 150b and the barrier layer 150a may or may not be doped with impurities by design.
＜ｐ型半導体層＞
　図３に示すように、第２の半導体層の一例としてのｐ型半導体層１６０は、通常、ｐクラッド層１６０ａおよびｐコンタクト層１６０ｂから構成される。また、ｐコンタクト層１６０ｂがｐクラッド層１６０ａを兼ねることも可能である。
　ｐクラッド層１６０ａは、発光層１５０へのキャリアの閉じ込めとキャリアの注入とを行なう層である。ｐクラッド層１６０ａとしては、発光層１５０のバンドギャップエネルギーより大きくなる組成であり、発光層１５０へのキャリアの閉じ込めができるものであれば特に限定されないが、好ましくは、ＡｌxＧａ1-xＮ（０＜ｘ≦０．４）のものが挙げられる。
　ｐクラッド層１６０ａが、このようなＡｌＧａＮからなると、発光層１５０へのキャリアの閉じ込めの点で好ましい。ｐクラッド層１６０ａの膜厚は、特に限定されないが、好ましくは１～４００ｎｍであり、より好ましくは５～１００ｎｍである。
　ｐクラッド層１６０ａのｐ型ドープ濃度は、１×１０18～１×１０21／ｃｍ3が好ましく、より好ましくは１×１０19～１×１０20／ｃｍ3である。ｐ型ドープ濃度が上記範囲であると、結晶性を低下させることなく良好なｐ型結晶が得られる。
　また、ｐクラッド層１６０ａは、複数回積層した超格子構造としてもよく、ＡｌＧａＮとＡｌＧａＮとの交互構造又はＡｌＧａＮとＧａＮとの交互構造であることが好ましい。 <P-type semiconductor layer>
As shown in FIG. 3, the p-type semiconductor layer 160 as an example of the second semiconductor layer is generally composed of a p-cladding layer 160a and a p-contact layer 160b. The p contact layer 160b can also serve as the p clad layer 160a.
The p-cladding layer 160a is a layer that performs confinement of carriers in the light emitting layer 150 and injection of carriers. The p-cladding layer 160a is not particularly limited as long as it has a composition larger than the band gap energy of the light-emitting layer 150 and can confine carriers in the light-emitting layer 150, but is preferably Al x Ga 1-x N. (0 <x ≦ 0.4).
It is preferable that the p-cladding layer 160a is made of such AlGaN from the viewpoint of confining carriers in the light-emitting layer 150. The thickness of the p-cladding layer 160a is not particularly limited, but is preferably 1 to 400 nm, and more preferably 5 to 100 nm.
The p-type doping concentration of the p-cladding layer 160a is preferably 1 × 10 18 to 1 × 10 21 / cm 3 , more preferably 1 × 10 19 to 1 × 10 20 / cm 3 . When the p-type dope concentration is in the above range, a good p-type crystal can be obtained without reducing the crystallinity.
The p-cladding layer 160a may have a superlattice structure in which a plurality of layers are stacked, and preferably has an alternating structure of AlGaN and AlGaN or an alternating structure of AlGaN and GaN.
　ｐコンタクト層１６０ｂは、第１の電極２１０を設けるための層である。ｐコンタクト層１６０ｂは、ＡｌxＧａ1-xＮ（０≦ｘ≦０．４）であることが好ましい。Ａｌ組成が上記範囲であると、良好な結晶性の維持および第１の電極２１０との良好なオーミック接触の維持が可能となる点で好ましい。
　ｐ型不純物（ドーパント）を１×１０18～１×１０21／ｃｍ3の濃度、好ましくは５×１０19～５×１０20／ｃｍ3の濃度で含有していると、良好なオーミック接触の維持、クラック発生の防止、良好な結晶性の維持の点で好ましい。ｐ型不純物としては、特に限定されないが、例えば好ましくはＭｇが挙げられる。
　ｐコンタクト層１６０ｂの膜厚は、特に限定されないが、０．０１～０．５μｍが好ましく、より好ましくは０．０５～０．２μｍである。ｐコンタクト層１６０ｂの膜厚がこの範囲であると、発光出力の点で好ましい。 The p contact layer 160 b is a layer for providing the first electrode 210. The p contact layer 160b is preferably Al x Ga 1-x N (0 ≦ x ≦ 0.4). When the Al composition is within the above range, it is preferable in that good crystallinity and good ohmic contact with the first electrode 210 can be maintained.
When a p-type impurity (dopant) is contained at a concentration of 1 × 10 18 to 1 × 10 21 / cm 3 , preferably 5 × 10 19 to 5 × 10 20 / cm 3 , good ohmic contact can be obtained. It is preferable in terms of maintenance, prevention of crack generation, and good crystallinity. Although it does not specifically limit as a p-type impurity, For example, Preferably Mg is mentioned.
The thickness of the p contact layer 160b is not particularly limited, but is preferably 0.01 to 0.5 μm, more preferably 0.05 to 0.2 μm. When the film thickness of the p contact layer 160b is within this range, it is preferable in terms of light emission output.
＜第１の電極＞
　次に、第１の電極２１０の構成について詳細に説明する。
　上述したように、第１の電極２１０は、透明電極１７０と、透明電極１７０上に積層される第１の接合層１９０と、第１の接合層１９０上に積層される第１のボンディングパッド電極２００とを有している。 <First electrode>
Next, the configuration of the first electrode 210 will be described in detail.
As described above, the first electrode 210 includes the transparent electrode 170, the first bonding layer 190 stacked on the transparent electrode 170, and the first bonding pad electrode stacked on the first bonding layer 190. 200.
＜透明電極＞
　図１に示すように、ｐ型半導体層１６０の上には透明電極１７０が積層されている。
　図２に示すように、平面視したときに、透明電極１７０（図１参照）は、第２の電極２４０を形成するために、エッチング等の手段によって一部が除去されたｐ型半導体層１６０の上面１６０ｃのほぼ全面を覆うように形成されているが、このような形状に限定されるわけでなく、隙間を開けて格子状や樹形状に形成してもよい。なお、透明電極１７０の構造も、従来公知の構造を含めて如何なる構造のものも何ら制限なく用いることができる。 <Transparent electrode>
As shown in FIG. 1, a transparent electrode 170 is stacked on the p-type semiconductor layer 160.
As shown in FIG. 2, when viewed in plan, the transparent electrode 170 (see FIG. 1) has a p-type semiconductor layer 160 partially removed by means such as etching to form the second electrode 240. However, the present invention is not limited to such a shape, and may be formed in a lattice shape or a tree shape with a gap. In addition, the structure of the transparent electrode 170 can be used without any limitation, including a conventionally known structure.
　透明電極１７０は、ｐ型半導体層１６０との接触抵抗が小さいものが好ましい。また、この半導体発光素子１では、発光層１５０からの光を第１の電極２１０が形成された側に取り出すことから、透明電極１７０は光透過性に優れたものが好ましい。さらにまた、ｐ型半導体層１６０の全面に渡って均一に電流を拡散させるために、透明電極１７０は優れた導電性を有していることが好ましい。 The transparent electrode 170 preferably has a small contact resistance with the p-type semiconductor layer 160. Moreover, in this semiconductor light emitting element 1, since the light from the light emitting layer 150 is taken out to the side where the first electrode 210 is formed, it is preferable that the transparent electrode 170 has excellent light transmittance. Furthermore, the transparent electrode 170 preferably has excellent conductivity in order to diffuse current uniformly over the entire surface of the p-type semiconductor layer 160.
　本実施の形態では、透明電極１７０として、Ｉｎを含む酸化物の導電性材料が用いられる。Ｉｎを含む酸化物の一部は、他の透明導電膜と比較して光透過性および導電性の両者がともに優れている点で好ましい。Ｉｎを含む導電性の酸化物としては、例えばＩＴＯ（酸化インジウム錫（Ｉｎ2Ｏ3－ＳｎＯ2））、ＩＺＯ（酸化インジウム亜鉛（Ｉｎ2Ｏ3－ＺｎＯ））、ＩＧＯ（酸化インジウムガリウム（Ｉｎ2Ｏ3－Ｇａ2Ｏ3））、ＩＣＯ（酸化インジウムセリウム（Ｉｎ2Ｏ3－ＣｅＯ2））等が挙げられる。なお、これらの中に、例えばフッ素などのドーパントが添加されていてもかまわない。
　これらの材料を、この技術分野でよく知られた慣用の手段で設けることによって、透明電極１７０を形成できる。また、透明電極１７０を形成した後に、透明電極１７０の透明化を目的とした熱アニールを施す場合もある。 In this embodiment, an oxide conductive material containing In is used as the transparent electrode 170. A part of the oxide containing In is preferable in that both light transmittance and conductivity are superior to other transparent conductive films. As the conductive oxide containing In, for example, ITO (indium tin oxide (In 2 O 3 —SnO 2 )), IZO (indium zinc oxide (In 2 O 3 —ZnO)), IGO (indium gallium oxide (In 2 O 3 —Ga 2 O 3 )), ICO (indium cerium oxide (In 2 O 3 —CeO 2 )) and the like. In addition, for example, a dopant such as fluorine may be added.
The transparent electrode 170 can be formed by providing these materials by conventional means well known in the art. In addition, after forming the transparent electrode 170, thermal annealing may be performed for the purpose of making the transparent electrode 170 transparent.
　本実施の形態において、透明電極１７０は、結晶化された構造のものを使用してよく、特に六方晶構造又はビックスバイト構造を有するＩｎ2Ｏ3結晶を含む透光性材料（例えば、ＩＴＯやＩＺＯ等）を好ましく使用することができる。
　例えば、六方晶構造のＩｎ2Ｏ3結晶を含むＩＺＯを透明電極１７０として使用する場合、エッチング性に優れたアモルファスのＩＺＯ膜を用いて特定形状に加工することができ、さらにその後、熱処理等によりアモルファス状態から結晶を含む構造に転移させることで、アモルファスのＩＺＯ膜よりも透光性の優れた電極に加工することができる。 In the present embodiment, the transparent electrode 170 may have a crystallized structure, and in particular, a translucent material containing an In 2 O 3 crystal having a hexagonal crystal structure or a bixbite structure (for example, ITO or IZO etc.) can be preferably used.
For example, when IZO containing an In 2 O 3 crystal having a hexagonal crystal structure is used as the transparent electrode 170, it can be processed into a specific shape using an amorphous IZO film having excellent etching properties, and then subjected to heat treatment or the like. By transitioning from an amorphous state to a structure including crystals, the electrode can be processed into a light-transmitting electrode better than an amorphous IZO film.
　また、ＩＺＯ膜としては、比抵抗が最も低くなる組成を使用することが好ましい。
　例えば、ＩＺＯ中のＺｎＯ濃度は１～２０質量％であることが好ましく、５～１５質量％の範囲であることが更に好ましい。１０質量％であると特に好ましい。また、ＩＺＯ膜の膜厚は、低比抵抗、高光透過率を得ることができる３５ｎｍ～１００００ｎｍ（１０μｍ）の範囲であることが好ましい。さらに、生産コストの観点から、ＩＺＯ膜の膜厚は１０００ｎｍ（１μｍ）以下であることが好ましい。
　ＩＺＯ膜のパターニングは、後述の熱処理工程を行なう前に行なうことが望ましい。熱処理により、アモルファス状態のＩＺＯ膜は結晶化されたＩＺＯ膜となるため、アモルファス状態のＩＺＯ膜と比較してエッチングが難しくなる。これに対し、熱処理前のＩＺＯ膜は、アモルファス状態であるため、周知のエッチング液（ＩＴＯ－０７Ｎエッチング液（関東化学社製））を用いて容易に精度良くエッチングすることが可能である。 Further, it is preferable to use a composition having the lowest specific resistance as the IZO film.
For example, the ZnO concentration in IZO is preferably 1 to 20% by mass, and more preferably 5 to 15% by mass. 10% by mass is particularly preferable. The film thickness of the IZO film is preferably in the range of 35 nm to 10000 nm (10 μm) at which low specific resistance and high light transmittance can be obtained. Furthermore, from the viewpoint of production cost, the thickness of the IZO film is preferably 1000 nm (1 μm) or less.
The patterning of the IZO film is preferably performed before the heat treatment process described later. By the heat treatment, the amorphous IZO film becomes a crystallized IZO film, which makes etching difficult compared to the amorphous IZO film. On the other hand, since the IZO film before heat treatment is in an amorphous state, it can be easily and accurately etched using a known etching solution (ITO-07N etching solution (manufactured by Kanto Chemical Co., Inc.)).
　アモルファス状態のＩＺＯ膜のエッチングは、ドライエッチング装置を用いて行なっても良い。このとき、エッチングガスにはＣｌ2、ＳｉＣｌ4、ＢＣｌ3等を用いることができる。アモルファス状態のＩＺＯ膜は、例えば５００℃～１０００℃の熱処理を行ない、条件を制御することで六方晶構造のＩｎ2Ｏ3結晶を含むＩＺＯ膜や、ビックスバイト構造のＩｎ2Ｏ3結晶を含むＩＺＯ膜にすることができる。六方晶構造のＩｎ2Ｏ3結晶を含むＩＺＯ膜は前述したようにエッチングし難いので、上述のエッチング処理の後に熱処理することが好ましい。 The amorphous IZO film may be etched using a dry etching apparatus. At this time, Cl 2 , SiCl 4 , BCl 3 or the like can be used as an etching gas. The amorphous IZO film includes, for example, an IZO film including a hexagonal structure In 2 O 3 crystal and a bixbite structure In 2 O 3 crystal by performing heat treatment at 500 ° C. to 1000 ° C. and controlling the conditions. An IZO film can be formed. Since an IZO film containing an In 2 O 3 crystal having a hexagonal crystal structure is difficult to etch as described above, it is preferable to perform a heat treatment after the above etching process.
　ＩＺＯ膜の熱処理は、Ｏ2を含まない雰囲気で行なうことが望ましく、Ｏ2を含まない雰囲気としては、Ｎ2雰囲気などの不活性ガス雰囲気や、またはＮ2などの不活性ガスとＨ2との混合ガス雰囲気などを挙げることができ、Ｎ2雰囲気、またはＮ2とＨ2との混合ガス雰囲気とすることが望ましい。なお、ＩＺＯ膜の熱処理をＮ2雰囲気、またはＮ2とＨ2との混合ガス雰囲気中で行なうと、例えば、ＩＺＯ膜を六方晶構造のＩｎ2Ｏ3結晶を含む膜に結晶化させるとともに、ＩＺＯ膜のシート抵抗を効果的に減少させることが可能である。
　また、ＩＺＯ膜の熱処理温度は、５００℃～１０００℃が好ましい。５００℃未満の温度で熱処理を行なった場合、ＩＺＯ膜を十分に結晶化できない恐れが生じ、ＩＺＯ膜の光透過率が十分に高いものとならない場合がある。１０００℃を超える温度で熱処理を行なった場合には、ＩＺＯ膜は結晶化されているが、ＩＺＯ膜の光透過率が十分に高いものとならない場合がある。また、１０００℃を超える温度で熱処理を行なった場合、ＩＺＯ膜の下にある半導体層を劣化させる恐れもある。 Heat treatment of the IZO film is preferably performed in an atmosphere containing no O 2, as the atmosphere containing no O 2, or an inert gas atmosphere such as N 2 atmosphere, or an inert gas such as N 2 and with H 2 etc. can be mentioned a mixed gas atmosphere, it is desirable that the mixed gas atmosphere of N 2 atmosphere or N 2 and H 2,. When the heat treatment of the IZO film is performed in an N 2 atmosphere or a mixed gas atmosphere of N 2 and H 2 , for example, the IZO film is crystallized into a film containing In 2 O 3 crystal having a hexagonal structure, It is possible to effectively reduce the sheet resistance of the IZO film.
Further, the heat treatment temperature of the IZO film is preferably 500 ° C. to 1000 ° C. When heat treatment is performed at a temperature lower than 500 ° C., the IZO film may not be sufficiently crystallized, and the light transmittance of the IZO film may not be sufficiently high. When heat treatment is performed at a temperature exceeding 1000 ° C., the IZO film is crystallized, but the light transmittance of the IZO film may not be sufficiently high. In addition, when heat treatment is performed at a temperature exceeding 1000 ° C., the semiconductor layer under the IZO film may be deteriorated.
　アモルファス状態のＩＺＯ膜を結晶化させる場合、成膜条件や熱処理条件などが異なるとＩＺＯ膜中の結晶構造が異なる。しかし、本発明の実施形態においては、接着層との接着性の点において、透明電極１７０は材料に限定されないが結晶性の材料の方が好ましく、特に結晶性ＩＺＯの場合にはビックスバイト結晶構造のＩｎ2Ｏ3結晶を含むＩＺＯであってもよく、六方晶構造のＩｎ2Ｏ3結晶を含むＩＺＯであってもよい。特に六方晶構造のＩｎ2Ｏ3結晶を含むＩＺＯがよい。
　特に、前述のように、熱処理によって結晶化したＩＺＯ膜は、アモルファス状態のＩＺＯ膜に比べて、第１の接合層１９０やｐ型半導体層１６０との密着性が良いため、本発明の実施形態において大変有効である。 In the case of crystallizing an amorphous IZO film, the crystal structure in the IZO film differs depending on the film formation conditions, heat treatment conditions, and the like. However, in the embodiment of the present invention, the transparent electrode 170 is not limited to a material in terms of adhesiveness to the adhesive layer, but is preferably a crystalline material, and particularly in the case of crystalline IZO, a bixbite crystal structure. IZO containing an In 2 O 3 crystal or IZO containing a hexagonal In 2 O 3 crystal may be used. In particular, IZO containing In 2 O 3 crystal having a hexagonal structure is preferable.
In particular, as described above, an IZO film crystallized by heat treatment has better adhesion to the first bonding layer 190 and the p-type semiconductor layer 160 than an amorphous IZO film. Is very effective.
＜第１の接合層＞
　接合層の一例としての第１の接合層１９０は、透明電極１７０に対する第１のボンディングパッド電極２００の接合強度を高めるために、透明電極１７０と第１のボンディングパッド電極２００との間に積層される。また、第１の接合層１９０は、透明電極１７０を透過して第１のボンディングパッド電極２００に照射される発光層１５０からの光を低損失で透過させるために、透光性を有していることが好ましい。 <First bonding layer>
The first bonding layer 190 as an example of the bonding layer is laminated between the transparent electrode 170 and the first bonding pad electrode 200 in order to increase the bonding strength of the first bonding pad electrode 200 to the transparent electrode 170. The In addition, the first bonding layer 190 has a light-transmitting property so as to transmit light from the light emitting layer 150 that is transmitted through the transparent electrode 170 and irradiated to the first bonding pad electrode 200 with low loss. Preferably it is.
　第１の接合層１９０は、弁作用金属（バルブメタル）で形成することが好ましく、Ａｌ、Ｔｉ、Ｚｎ、Ｚｒ、Ｗ、Ｎｂ、Ｍｇ、Ｂｉ、Ｓｉ、Ｈｆ、Ｔａからなる群より選ばれた少なくとも一種の元素を含むとともに透明電極１７０と接する側がこれらの元素の窒化物または酸化物の少なくともいずれか一方を含むように透明電極１７０上に積層されることがより好ましい。また、これらの元素からなる金属を一部窒化させたものまたは一部酸化させたものを含む構成としてもよい。これにより、弁作用金属そのもので第１の接合層１９０を構成した場合と比較して、透明電極１７０と第１のボンディングパッド電極２００との接合強度をより向上させることができる。 The first bonding layer 190 is preferably formed of a valve metal (valve metal), and is selected from the group consisting of Al, Ti, Zn, Zr, W, Nb, Mg, Bi, Si, Hf, and Ta. It is more preferable that the transparent electrode 170 is laminated so that the side containing at least one element and in contact with the transparent electrode 170 contains at least one of a nitride or an oxide of these elements. Further, a structure including a partially nitrided or partially oxidized metal made of these elements may be used. Thereby, compared with the case where the 1st joining layer 190 is comprised with the valve action metal itself, the joint strength of the transparent electrode 170 and the 1st bonding pad electrode 200 can be improved more.
　また、第１の接合層１９０は、Ｔａ、Ｗ、Ｔｉからなる群より選ばれた少なくとも一種の元素を含むとともに透明電極１７０と接する側がこれらの元素の窒化物を含むように透明電極１７０上に積層されることがより好ましい。また、元素からなる金属を一部窒化させたものを含む構成としてもよい。これは、接合層金属中の窒化部が、金属酸化物である透明電極１７０との接合強度を向上させるためである。特に、Ｔａ、Ｗ、Ｔｉ等の金属は弁作用金属の中でもイオン化しにくい性質を持つため、これらを窒化させたものを含めることによって、水（水分）の存在下における電気化学反応により接合金属元素がイオン化して溶出することを防ぐことができ、好ましい。これにより、透明電極１７０に対する第１のボンディングパッド電極２００の接合強度を格段に高めることができる。 Further, the first bonding layer 190 includes at least one element selected from the group consisting of Ta, W, and Ti, and on the transparent electrode 170 so that the side in contact with the transparent electrode 170 includes a nitride of these elements. More preferably, they are laminated. In addition, a structure including a part of the element metal nitrided may be used. This is because the nitriding portion in the bonding layer metal improves the bonding strength with the transparent electrode 170 that is a metal oxide. In particular, metals such as Ta, W, and Ti have the property that they are difficult to ionize among valve metals, and therefore, by including these nitridated metals, the bonding metal element is formed by an electrochemical reaction in the presence of water (moisture). Can be prevented from being ionized and eluted, which is preferable. Thereby, the bonding strength of the first bonding pad electrode 200 to the transparent electrode 170 can be significantly increased.
　また、第１の接合層１９０のすべてすなわち全体が弁作用金属の窒化物で構成されていてもよいが、少なくとも部分的、局所的あるいは薄膜状に透明電極１７０と接する側が弁作用金属の窒化物で形成されていればよい。したがって、第１の接合層１９０が、透明電極１７０側に形成される弁作用金属窒化物層と第１のボンディングパッド電極２００側に形成される弁作用金属層とで形成されていてもかまわない。 In addition, all of the first bonding layer 190, that is, the whole may be made of a valve action metal nitride, but at least partially, locally or thinly in contact with the transparent electrode 170 is a valve action metal nitride. What is necessary is just to be formed. Therefore, the first bonding layer 190 may be formed of a valve action metal nitride layer formed on the transparent electrode 170 side and a valve action metal layer formed on the first bonding pad electrode 200 side. .
　この場合に、第１の接合層１９０は厚みが１０オングストローム以上２０００オングストローム以下の範囲の薄膜であること、より好ましくは２０オングストローム以上１０００オングストローム以下の範囲の薄膜であることが好ましい。これにより、発光層１５０からの光を遮ることなく効果的に透過させることができる。なお、厚みが１０オングストローム未満になると、第１の接合層１９０の強度が低下し、これにより透明電極１７０に対する第１のボンディングパッド電極２００の接合強度が低下する恐れがある。第１の接合層１９０における金属窒化物層の厚さは約５～５０オングストロームが好ましい。５オングストローム以下では透明電極１７０との接合強度の向上効果が少なくなり、５０オングストローム以上では、第１の接合層１９０と透明電極１７０との導電性の低下を招く恐れがある。また、金属窒化物層の厚さが２００オングストローム以上では、光の透過率、反射率が低下するので好ましくない。 In this case, the first bonding layer 190 is preferably a thin film having a thickness in the range of 10 angstroms to 2000 angstroms, more preferably in the range of 20 angstroms to 1000 angstroms. Thereby, the light from the light emitting layer 150 can be effectively transmitted without being blocked. Note that if the thickness is less than 10 angstroms, the strength of the first bonding layer 190 is lowered, which may reduce the bonding strength of the first bonding pad electrode 200 to the transparent electrode 170. The thickness of the metal nitride layer in the first bonding layer 190 is preferably about 5 to 50 angstroms. If it is 5 angstroms or less, the effect of improving the bonding strength with the transparent electrode 170 is reduced, and if it is 50 angstroms or more, the conductivity between the first bonding layer 190 and the transparent electrode 170 may be lowered. Further, when the thickness of the metal nitride layer is 200 angstroms or more, the light transmittance and the reflectance are lowered, which is not preferable.
　また、第１の接合層１９０は、Ｔａ、Ｎｂ、Ｔｉからなる群より選ばれた少なくとも一種の元素を含むとともに透明電極１７０と接する側がこれらの元素の酸化物を含むように透明電極１７０上に積層されることがより好ましい。また、これらの元素からなる金属を一部酸化させたものを含む構成としてもよい。これは、第１の接合層１９０を構成する金属中の酸化部が、金属酸化物である透明電極１７０との接合強度を向上させるためである。特に、Ｔａ、Ｎｂ、Ｔｉ等の金属は弁作用金属の中でもイオン化しにくい性質を持つため、これらを酸化させたものを含めることによって、水（水分）の存在下における電気化学反応により接合金属元素がイオン化して溶出することを防ぐことができ、好ましい。これにより、透明電極１７０に対する第１のボンディングパッド電極２００の接合強度を格段に高めることができる。 Further, the first bonding layer 190 includes at least one element selected from the group consisting of Ta, Nb, and Ti, and on the transparent electrode 170 so that the side in contact with the transparent electrode 170 includes an oxide of these elements. More preferably, they are laminated. Moreover, it is good also as a structure containing what oxidized the metal which consists of these elements partially. This is because the oxidized portion in the metal constituting the first bonding layer 190 improves the bonding strength with the transparent electrode 170 that is a metal oxide. In particular, metals such as Ta, Nb, and Ti have the property that they are difficult to ionize among valve metals. Therefore, by including these oxidized metals, bonding metal elements can be formed by an electrochemical reaction in the presence of water (moisture). Can be prevented from being ionized and eluted, which is preferable. Thereby, the bonding strength of the first bonding pad electrode 200 to the transparent electrode 170 can be significantly increased.
　また、第１の接合層１９０のすべてすなわち全体が弁作用金属の酸化物で構成されていてもよいが、少なくとも部分的、局所的あるいは薄膜状に透明電極１７０と接する側が弁作用金属の酸化物で形成されていればよい。したがって、第１の接合層１９０が、透明電極１７０側に形成される弁作用金属酸化物層と第１のボンディングパッド電極２００側に形成される弁作用金属層とで形成されていてもかまわない。 Further, all of the first bonding layer 190, that is, the whole may be composed of an oxide of the valve action metal, but the oxide layer of the valve action metal is at least partially, locally or thinly in contact with the transparent electrode 170. What is necessary is just to be formed. Accordingly, the first bonding layer 190 may be formed of a valve action metal oxide layer formed on the transparent electrode 170 side and a valve action metal layer formed on the first bonding pad electrode 200 side. .
　この場合に、第１の接合層１９０は厚みが５オングストローム以上１０００オングストローム以下の範囲の薄膜であること、より好ましくは１０オングストローム以上４００オングストローム以下の範囲の薄膜であることが好ましい。これにより、発光層１５０からの光を遮ることなく効果的に透過させることができる。なお、厚みが５オングストローム未満になると、第１の接合層１９０の強度が低下し、これにより透明電極１７０に対する第１のボンディングパッド電極２００の接合強度が低下する恐れがある。第１の接合層１９０における金属酸化物層の厚さは約５～５０オングストロームが好ましい。５オングストローム以下では透明電極１７０との接合強度の向上効果が少なくなり、５０オングストローム以上では、第１の接合層１９０と透明電極１７０との導電性の低下を招く恐れがある。 In this case, the first bonding layer 190 is preferably a thin film having a thickness in the range of 5 angstroms to 1000 angstroms, more preferably in the range of 10 angstroms to 400 angstroms. Thereby, the light from the light emitting layer 150 can be effectively transmitted without being blocked. Note that when the thickness is less than 5 angstroms, the strength of the first bonding layer 190 is lowered, and thus the bonding strength of the first bonding pad electrode 200 to the transparent electrode 170 may be lowered. The thickness of the metal oxide layer in the first bonding layer 190 is preferably about 5 to 50 angstroms. If it is 5 angstroms or less, the effect of improving the bonding strength with the transparent electrode 170 is reduced, and if it is 50 angstroms or more, the conductivity between the first bonding layer 190 and the transparent electrode 170 may be lowered.
＜第１のボンディングパッド電極＞
　図１に示すように、接続電極および第１の接続電極の一例としての第１のボンディングパッド電極２００は、透明電極１７０側から順に、第１のバリア層２００ａと第１のボンディング層２００ｂとが積層された積層体からなる。バリア層の一例としての第１のバリア層２００ａは、第１のボンディング層２００ｂを形成する元素のマイグレーションをバリアする作用を有し、ボンディング層の一例としての第１のボンディング層２００ｂは、給電用の外部端子材料との密着性を高める作用がある。
　なお、第１のボンディングパッド電極２００は、第１のバリア層２００ａのみからなる単層構造であってもよく、第１のバリア層２００ａと第１のボンディング層２００ｂとの間に、第１のボンディングパッド電極２００全体の強度を強化する別のバリア層をさらに挿入して、三層構造としてもよい。また、第１のバリア層２００ａに代えてバリア層を挿入して、二層構造としてもよい。 <First bonding pad electrode>
As shown in FIG. 1, the first bonding pad electrode 200 as an example of the connection electrode and the first connection electrode includes a first barrier layer 200a and a first bonding layer 200b in order from the transparent electrode 170 side. It consists of the laminated body laminated | stacked. The first barrier layer 200a as an example of the barrier layer has a function of blocking migration of elements forming the first bonding layer 200b, and the first bonding layer 200b as an example of the bonding layer is used for supplying power. There is an effect of improving the adhesion to the external terminal material.
Note that the first bonding pad electrode 200 may have a single-layer structure including only the first barrier layer 200a, and the first bonding pad electrode 200 is provided between the first barrier layer 200a and the first bonding layer 200b. Another barrier layer that enhances the strength of the entire bonding pad electrode 200 may be further inserted to form a three-layer structure. Alternatively, a barrier layer may be inserted instead of the first barrier layer 200a to form a two-layer structure.
＜第１のバリア層＞
　図１に示す第１のバリア層２００ａは、第１のボンディングパッド電極２００全体の強度を強化する役割を有している。このため、比較的強固な金属材料を使用することが好ましく、例えば、Ａｇ、Ａｌ、Ｒｕ、Ｒｈ、Ｐｄ、Ｏｓ、Ｉｒ、Ｐｔ、Ｔｉ、Ｗ、Ｍｏ、Ｎｉ、Ｃｏ、Ｚｒ、Ｈｆ、Ｔａ、Ｎｂのうちの何れかまたはこれら金属の何れかを含む合金からなるものが選べる。また、第１のバリア層２００ａは、発光層１５０から出射された光を反射させるために、反射率の高い金属で構成することが好ましく、Ｒｕ、Ｒｈ、Ｐｄ、Ｏｓ、Ｉｒ、Ｐｔ等の白金族金属、Ａｌ、Ａｇ、Ｔｉおよびこれらの金属の少なくも一種を含む合金で構成することがより好ましい。これにより、発光層１５０からの光を効果的に反射させることができる。
　なかでも、Ａｌ、Ａｇ、Ｐｔおよびこれらの金属の少なくとも一種を含む合金は、電極用の材料として一般的であり、入手のし易さ、取り扱いの容易さなどの点から優れている。
　また、第１のバリア層２００ａは、高い反射率を有する金属で形成した場合、厚さが２００～３０００オングストロームであることが望ましい。第１のバリア層２００ａが薄すぎると充分な反射の効果が得られない。一方、厚すぎると特に利点は生じず、工程時間の長時間化と材料の無駄を生じるのみである。更に望ましくは、５００～２０００オングストロームである。 <First barrier layer>
The first barrier layer 200a shown in FIG. 1 has a role of enhancing the strength of the first bonding pad electrode 200 as a whole. For this reason, it is preferable to use a relatively strong metal material, for example, Ag, Al, Ru, Rh, Pd, Os, Ir, Pt, Ti, W, Mo, Ni, Co, Zr, Hf, Ta, One made of an alloy containing any of Nb or any of these metals can be selected. The first barrier layer 200a is preferably made of a highly reflective metal to reflect the light emitted from the light emitting layer 150, and is made of platinum such as Ru, Rh, Pd, Os, Ir, and Pt. More preferably, it is composed of a group metal, Al, Ag, Ti, and an alloy containing at least one of these metals. Thereby, the light from the light emitting layer 150 can be reflected effectively.
Among these, Al, Ag, Pt, and alloys containing at least one of these metals are generally used as electrode materials, and are excellent in terms of easy availability and handling.
Further, when the first barrier layer 200a is formed of a metal having a high reflectance, it is desirable that the thickness is 200 to 3000 angstroms. If the first barrier layer 200a is too thin, a sufficient reflection effect cannot be obtained. On the other hand, if it is too thick, there is no particular advantage, and only a long process time and material waste are caused. More preferably, it is 500 to 2000 angstroms.
　また、第１のバリア層２００ａは、第１の接合層１９０に密着していることが、発光層１５０からの光を効率良く反射するとともに、第１のボンディングパッド電極２００との接合強度を高められる点で好ましい。第１のボンディングパッド電極２００が充分な強度を得るためには、第１のバリア層２００ａが第１の接合層１９０を介して透明電極１７０に強固に接合されていることが必要である。最低限、一般的な方法でボンディングパッドに金線を接続する工程で剥離しない程度の強度が好ましい。特に、Ｒｈ、Ｐｄ、Ｉｒ、Ｐｔおよびこれらの金属の少なくも一種を含む合金は、光の反射性などの点から第１のバリア層２００ａとして好適に使用される。 The first barrier layer 200a is in close contact with the first bonding layer 190, so that the light from the light emitting layer 150 is efficiently reflected and the bonding strength with the first bonding pad electrode 200 is increased. This is preferable. In order for the first bonding pad electrode 200 to obtain sufficient strength, the first barrier layer 200 a needs to be firmly bonded to the transparent electrode 170 via the first bonding layer 190. At a minimum, a strength that does not cause peeling in the step of connecting the gold wire to the bonding pad by a general method is preferable. In particular, Rh, Pd, Ir, Pt, and an alloy containing at least one of these metals are preferably used as the first barrier layer 200a in view of light reflectivity.
　また、第１のボンディングパッド電極２００の反射率は、第１のバリア層２００ａの構成材料によって大きく変わるが、６０％以上であることが望ましい。更には、８０％以上であることが望ましく、９０％以上であればなお良い。反射率は、分光光度計等で比較的容易に測定することが可能である。しかし、第１のボンディングパッド電極２００そのものは面積が小さいために反射率を測定することは難しい。そこで、透明な例えばガラス製の、面積の大きい「ダミー基板」をボンディングパッド電極形成時にチャンバに入れて、同時にダミー基板上に同じボンディングパッド電極を作成して測定するなどの方法を用いて測定することができる。 The reflectivity of the first bonding pad electrode 200 varies greatly depending on the constituent material of the first barrier layer 200a, but is preferably 60% or more. Further, it is preferably 80% or more, and more preferably 90% or more. The reflectance can be measured relatively easily with a spectrophotometer or the like. However, since the first bonding pad electrode 200 itself has a small area, it is difficult to measure the reflectance. Therefore, a transparent “dummy substrate” made of glass, for example, having a large area is placed in the chamber when forming the bonding pad electrode, and at the same time, the same bonding pad electrode is created on the dummy substrate and measured. be able to.
＜第１のボンディング層＞
　図１に示す第１のボンディング層２００ｂは、Ａｕ、Ａｌまたはこれらの金属の少なくとも一種を含む合金からなることが好ましい。ＡｕおよびＡｌはボンディングボールとして使用されることが多い金ボールとの密着性の良い金属なので、Ａｕ、Ａｌまたはこれらの金属の少なくも一種を含む合金を用いることにより、ボンディングワイヤとの密着性に優れたものとすることができる。中でも、特に望ましいのはＡｕである。
　また、第１のボンディング層２００ｂの厚みは、５００オングストローム以上２００００オングストローム以下の範囲であることが好ましく、更に望ましくは５０００オングストローム以上１５０００オングストローム以下である。
　第１のボンディング層２００ｂが薄すぎるとボンディングボールとの密着性が悪くなり、厚すぎても特に利点は生ぜず、コスト増大を招くのみである。 <First bonding layer>
The first bonding layer 200b shown in FIG. 1 is preferably made of Au, Al, or an alloy containing at least one of these metals. Since Au and Al are metals with good adhesion to gold balls that are often used as bonding balls, the use of Au, Al or an alloy containing at least one of these metals improves adhesion to bonding wires. It can be excellent. Of these, Au is particularly desirable.
The thickness of the first bonding layer 200b is preferably in the range of 500 angstroms or more and 20000 angstroms or less, and more preferably 5000 angstroms or more and 15000 angstroms or less.
If the first bonding layer 200b is too thin, the adhesion to the bonding ball is deteriorated. If the first bonding layer 200b is too thick, no particular advantage is produced and only the cost is increased.
　第１のボンディングパッド電極２００に向かった光は、第１のボンディングパッド電極２００の最下面（透明電極１７０側の面）の第１のバリア層２００ａで反射され、一部は散乱されて横方向あるいは斜め方向に進み、一部は第１のボンディングパッド電極２００の直下に進む。散乱されて横方向や斜め方向に進んだ光は、半導体発光素子１の側面から外部に取り出される。一方、第１のボンディングパッド電極２００の直下の方向に進んだ光は、半導体発光素子１の下面でさらに散乱や反射されて、側面や透明電極１７０（上に第１のボンディングパッド電極２００が存在しない部分）を通じて外部へ取り出される。 The light traveling toward the first bonding pad electrode 200 is reflected by the first barrier layer 200a on the lowermost surface (the surface on the transparent electrode 170 side) of the first bonding pad electrode 200, and part of the light is scattered and laterally Alternatively, the process proceeds in an oblique direction, and a part thereof proceeds directly below the first bonding pad electrode 200. The light that is scattered and travels in the lateral direction or the oblique direction is extracted from the side surface of the semiconductor light emitting element 1 to the outside. On the other hand, the light traveling in the direction immediately below the first bonding pad electrode 200 is further scattered and reflected by the lower surface of the semiconductor light emitting element 1, and the side surface and the transparent electrode 170 (the first bonding pad electrode 200 exists on the side surface). Taken out).
　第１の接合層１９０およびこれに積層される第１のボンディングパッド電極２００は、透明電極１７０の上であれば、どこへでも形成することができる。例えば第２の電極２４０から最も遠い位置に形成してもよいし、半導体発光素子１の中心などに形成してもよい。しかし、あまりにも第２の電極２４０に近接した位置に形成すると、ボンディングした際にワイヤ間、ボール間のショートを生じてしまうため好ましくない。
　また、第１のボンディングパッド電極２００の電極面積としては、できるだけ大きいほうがボンディング作業はしやすいものの、発光の取り出しの妨げになる。例えば、チップ面の面積の半分を超えるような面積を覆っては、発光の取り出しの妨げとなり、出力が著しく低下する。逆に小さすぎるとボンディング作業がしにくくなり、製品の収率を低下させる。
　具体的には、ボンディングボールの直径よりもわずかに大きい程度が好ましく、直径１００μｍの円形程度であることが一般的である。 The first bonding layer 190 and the first bonding pad electrode 200 laminated thereon can be formed anywhere as long as it is on the transparent electrode 170. For example, it may be formed at a position farthest from the second electrode 240 or may be formed at the center of the semiconductor light emitting element 1 or the like. However, if it is formed at a position too close to the second electrode 240, it is not preferable because a short circuit between wires and balls occurs when bonding.
Further, as the electrode area of the first bonding pad electrode 200 is as large as possible, the bonding operation is easier, but the emission of light emission is hindered. For example, covering an area that exceeds half the area of the chip surface hinders the extraction of light emission, and the output is significantly reduced. On the other hand, if it is too small, the bonding work becomes difficult and the yield of the product is lowered.
Specifically, it is preferably slightly larger than the diameter of the bonding ball, and generally has a circular shape with a diameter of 100 μm.
＜第２の電極＞
　続いて、第２の電極２４０の構成の一例について詳細に説明する。
　上述したように、第２の電極２４０は、第２の接合層２２０と、第２の接合層２２０上に積層される第２のボンディングパッド電極２３０とを有している。
　図１に示すように、ｎ型半導体層１４０の半導体層露出面１４０ｃに第２の電極２４０が形成されている。このように、第２の電極２４０を形成する際には、エッチング等の手段によって発光層１５０およびｐ型半導体層１６０の一部を切り欠け除去してｎ型半導体層１４０のｎコンタクト層１４０ａを露出させ、得られた半導体層露出面１４０ｃ上に第２の電極２４０を形成する。
　図２に示すように、平面視したときに、第２の電極２４０は円形状とされているが、このような形状に限定されるわけでなく、多角形状など任意の形状とすることができる。また、第２の電極２４０はボンディングパットを兼ねており、ボンディングワイヤを接続することができる構成とされている。 <Second electrode>
Next, an example of the configuration of the second electrode 240 will be described in detail.
As described above, the second electrode 240 includes the second bonding layer 220 and the second bonding pad electrode 230 stacked on the second bonding layer 220.
As shown in FIG. 1, the second electrode 240 is formed on the semiconductor layer exposed surface 140 c of the n-type semiconductor layer 140. As described above, when the second electrode 240 is formed, a part of the light emitting layer 150 and the p-type semiconductor layer 160 is cut off and removed by means such as etching, so that the n-contact layer 140a of the n-type semiconductor layer 140 is removed. The second electrode 240 is formed on the exposed semiconductor layer exposed surface 140c.
As shown in FIG. 2, the second electrode 240 has a circular shape when seen in a plan view, but is not limited to such a shape, and may have an arbitrary shape such as a polygonal shape. . Further, the second electrode 240 also serves as a bonding pad and is configured to be able to connect a bonding wire.
＜第２の接合層＞
　第２の接合層２２０は、ｎ型半導体層１４０のｎコンタクト層１４０ａに形成される半導体層露出面１４０ｃに対する第２のボンディングパッド電極２３０の接合強度を高めるために、ｎコンタクト層１４０ａと第２のボンディングパッド電極２３０との間に積層される。なお、本実施の形態では、ｎコンタクト層１４０ａが一つの半導体層に対応している。 <Second bonding layer>
The second bonding layer 220 includes a second bonding layer 140a and a second bonding layer 140a in order to increase the bonding strength of the second bonding pad electrode 230 to the semiconductor layer exposed surface 140c formed in the n contact layer 140a of the n-type semiconductor layer 140. And the bonding pad electrode 230. In the present embodiment, the n contact layer 140a corresponds to one semiconductor layer.
　第２の接合層２２０は、第１の接合層１９０と同様に、弁作用金属（バルブメタル）すなわちＡｌ、Ｔｉ、Ｚｎ、Ｚｒ、Ｗ、Ｎｂ、Ｍｇ、Ｂｉ、Ｓｉ、Ｈｆ、Ｔａからなる群より選ばれた少なくとも一種の元素を含むとともに半導体層露出面１４０ｃと接する側が元素の酸化物または窒化物の少なくともいずれか一方を含むように半導体層露出面１４０ｃ上に積層された構成とすることがより好ましい。これにより、弁作用金属そのもので第２の接合層２２０を構成した場合と比較して、ｎコンタクト層１４０ａと第２のボンディングパッド電極２３０との接合強度をより向上させることができる。 Similarly to the first bonding layer 190, the second bonding layer 220 is a valve metal (valve metal), that is, a group consisting of Al, Ti, Zn, Zr, W, Nb, Mg, Bi, Si, Hf, and Ta. The semiconductor layer is exposed on the semiconductor layer exposed surface 140c so as to include at least one element selected from the above and the side in contact with the semiconductor layer exposed surface 140c includes at least one of an oxide and a nitride of the element. More preferred. Thereby, the bonding strength between the n contact layer 140a and the second bonding pad electrode 230 can be further improved as compared with the case where the second bonding layer 220 is formed of the valve metal itself.
　また、第２の接合層２２０は、Ｔａ、Ｗ、Ｔｉからなる群より選ばれた少なくとも一種の元素を窒化させたものにて構成することがより好ましい。特に、Ｔａ、Ｗ、Ｔｉ等の金属を窒化させたものを用いることによって、ｎコンタクト層１４０ａに対する第２のボンディングパッド電極２３０の接合強度を格段に高めることができる。 Further, it is more preferable that the second bonding layer 220 is made of a material obtained by nitriding at least one element selected from the group consisting of Ta, W, and Ti. In particular, by using a material obtained by nitriding a metal such as Ta, W, or Ti, the bonding strength of the second bonding pad electrode 230 to the n contact layer 140a can be remarkably increased.
　ただし、第２の接合層２２０のすべてすなわち全体が弁作用金属の窒化物で構成されている必要はなく、少なくともｎコンタクト層１４０ａと接する側が弁作用金属の窒化物で形成されていればよい。したがって、第２の接合層２２０が、ｎコンタクト層１４０ａ側に形成される弁作用金属窒化物層と第２のボンディングパッド電極２３０側に形成される弁作用金属層とで形成されていてもかまわない。また、第２の接合層２２０は、ｎコンタクト層１４０ａ側と公知な透明電極材料の層を介して積層されてもよい。この場合、公知な透明電極材料の層は、ｎコンタクト層１４０ａ側と接合する接合層の機能を有する。 However, all of the second bonding layer 220, that is, the entire layer does not need to be made of a nitride of valve action metal, and at least the side in contact with the n contact layer 140a may be made of nitride of the valve action metal. Therefore, the second bonding layer 220 may be formed of a valve action metal nitride layer formed on the n contact layer 140a side and a valve action metal layer formed on the second bonding pad electrode 230 side. Absent. Further, the second bonding layer 220 may be laminated via the n-contact layer 140a side and a known transparent electrode material layer. In this case, the layer of a known transparent electrode material has a function of a bonding layer bonded to the n contact layer 140a side.
　この場合に、第２の接合層２２０は厚みが１０オングストローム以上２０００オングストローム以下の範囲の薄膜であること、より好ましくは２０オングストローム以上１０００オングストローム以下の範囲の薄膜であることが好ましい。なお、厚みが１０オングストローム未満になると、第２の接合層２２０の強度が低下し、これによりｎコンタクト層１４０ａに対する第２のボンディングパッド電極２３０の接合強度が低下するので好ましくない。 In this case, the second bonding layer 220 is preferably a thin film having a thickness in the range of 10 angstroms to 2000 angstroms, more preferably in the range of 20 angstroms to 1000 angstroms. Note that if the thickness is less than 10 angstroms, the strength of the second bonding layer 220 is decreased, which is not preferable because the bonding strength of the second bonding pad electrode 230 to the n contact layer 140a is decreased.
　また、第２の接合層２２０は、Ｔａ、Ｎｂ、Ｔｉからなる群より選ばれた少なくとも一種の元素を酸化させたものにて構成することがより好ましい。特に、Ｔｂ、Ｎｂ、Ｔｉ等の金属を酸化させたものを用いることによって、ｎコンタクト層１４０ａに対する第２のボンディングパッド電極２３０の接合強度を格段に高めることができる。 Further, it is more preferable that the second bonding layer 220 is made of an oxide of at least one element selected from the group consisting of Ta, Nb, and Ti. In particular, the bonding strength of the second bonding pad electrode 230 to the n contact layer 140a can be significantly increased by using an oxidized metal such as Tb, Nb, or Ti.
　ただし、第２の接合層２２０のすべてすなわち全体が弁作用金属の酸化物で構成されている必要はなく、少なくともｎコンタクト層１４０ａと接する側が弁作用金属の酸化物で形成されていればよい。したがって、第２の接合層２２０が、ｎコンタクト層１４０ａ側に形成される弁作用金属酸化物層と第２のボンディングパッド電極２３０側に形成される弁作用金属層とで形成されていてもかまわない。また、第２の接合層２２０は、ｎコンタクト層１４０ａ側と公知な透明電極材料の層を介して積層されてもよい。この場合、公知な透明電極材料の層は、ｎコンタクト層１４０ａ側と接合する接合層の機能を有する。 However, it is not necessary that all of the second bonding layer 220, that is, the whole is made of an oxide of the valve action metal, and it is sufficient that at least the side in contact with the n contact layer 140a is made of the oxide of the valve action metal. Therefore, the second bonding layer 220 may be formed of a valve action metal oxide layer formed on the n contact layer 140a side and a valve action metal layer formed on the second bonding pad electrode 230 side. Absent. Further, the second bonding layer 220 may be laminated via the n-contact layer 140a side and a known transparent electrode material layer. In this case, the layer of a known transparent electrode material has a function of a bonding layer bonded to the n contact layer 140a side.
　この場合に、第２の接合層２２０は厚みが５オングストローム以上１０００オングストローム以下の範囲の薄膜であること、より好ましくは１０オングストローム以上４００オングストローム以下の範囲の薄膜であることが好ましい。なお、厚みが５オングストローム未満になると、第２の接合層２２０の強度が低下し、これによりｎコンタクト層１４０ａに対する第２のボンディングパッド電極２３０の接合強度が低下するので好ましくない。 In this case, the second bonding layer 220 is preferably a thin film having a thickness in the range of 5 angstroms to 1000 angstroms, more preferably in the range of 10 angstroms to 400 angstroms. Note that if the thickness is less than 5 angstroms, the strength of the second bonding layer 220 is lowered, and as a result, the bonding strength of the second bonding pad electrode 230 to the n-contact layer 140a is not preferable.
＜第２のボンディングパッド電極＞
　図１に示すように、第２の接続電極の一例としての第２のボンディングパッド電極２３０は、ｎコンタクト層１４０ａ（図３参照）側から順に、第２のバリア層２３０ａと第２のボンディング層２３０ｂとが積層された積層体からなる。
　なお、第２のボンディングパッド電極２３０は、第２のバリア層２３０ａのみからなる単層構造であってもよく、第２のバリア層２３０ａと第２のボンディング層２３０ｂとの間に、第２のボンディングパッド電極２３０全体の強度を強化する別のバリア層をさらに挿入して、三層構造としてもよい。また、第２のバリア層２３０ａに代えてバリア層を挿入して、二層構造としてもよい。 <Second bonding pad electrode>
As shown in FIG. 1, the second bonding pad electrode 230 as an example of the second connection electrode includes a second barrier layer 230a and a second bonding layer in order from the n contact layer 140a (see FIG. 3) side. 230b is laminated.
Note that the second bonding pad electrode 230 may have a single-layer structure including only the second barrier layer 230a, and the second bonding pad electrode 230 is provided between the second barrier layer 230a and the second bonding layer 230b. Another barrier layer that enhances the strength of the entire bonding pad electrode 230 may be further inserted to form a three-layer structure. Alternatively, a barrier layer may be inserted instead of the second barrier layer 230a to form a two-layer structure.
＜第２のバリア層＞
　図１に示す第２のバリア層２３０ａは、第１のバリア層２００ａと同様に第２のボンディングパッド電極２３０全体の強度を強化する役割を有している。このため、比較的強固な金属材料を使用することが好ましく、例えば、Ａｇ、Ａｌ、Ｒｕ、Ｒｈ、Ｐｄ、Ｏｓ、Ｉｒ、Ｐｔ、Ｔｉ、Ｗ、Ｍｏ、Ｎｉ、Ｃｏ、Ｚｒ、Ｈｆ、Ｔａ、Ｎｂのうちの何れかまたはこれら金属の何れかを含む合金からなるものが選べる。なお、本実施の形態では、第２のバリア層２３０ａを、第１のバリア層２００ａと同様に、Ｒｕ、Ｒｈ、Ｐｄ、Ｏｓ、Ｉｒ、Ｐｔ等の白金族金属、Ａｌ、Ａｇ、Ｔｉおよびこれらの金属の少なくも一種を含む合金で構成することがより好ましい。 <Second barrier layer>
The second barrier layer 230a shown in FIG. 1 has a role of enhancing the strength of the entire second bonding pad electrode 230, similarly to the first barrier layer 200a. For this reason, it is preferable to use a relatively strong metal material, for example, Ag, Al, Ru, Rh, Pd, Os, Ir, Pt, Ti, W, Mo, Ni, Co, Zr, Hf, Ta, One made of an alloy containing any of Nb or any of these metals can be selected. In the present embodiment, the second barrier layer 230a is made of a platinum group metal such as Ru, Rh, Pd, Os, Ir, Pt, Al, Ag, Ti, and the like, like the first barrier layer 200a. More preferably, it is made of an alloy containing at least one of these metals.
　また、第２のバリア層２３０ａは、第２の接合層２２０に密着していることが、第２のボンディングパッド電極２３０との接合強度を高められる点で好ましい。第２のボンディングパッド電極２３０が充分な強度を得るためには、第２のバリア層２３０ａが第２の接合層２２０を介してｎコンタクト層１４０ａに強固に接合されていることが必要である。最低限、一般的な方法でボンディングパッドに金線を接続する工程で剥離しない程度の強度が好ましい。特に、Ｒｈ、Ｐｄ、Ｉｒ、Ｐｔおよびこれらの金属の少なくも一種を含む合金は、第２のバリア層２３０ａとして好適に使用される。 In addition, it is preferable that the second barrier layer 230a is in close contact with the second bonding layer 220 in terms of enhancing the bonding strength with the second bonding pad electrode 230. In order for the second bonding pad electrode 230 to obtain sufficient strength, the second barrier layer 230 a needs to be firmly bonded to the n contact layer 140 a via the second bonding layer 220. At a minimum, a strength that does not cause peeling in the step of connecting the gold wire to the bonding pad by a general method is preferable. In particular, Rh, Pd, Ir, Pt and an alloy containing at least one of these metals are preferably used as the second barrier layer 230a.
＜第２のボンディング層＞
　図１に示す第２のボンディング層２３０ｂは、第１のボンディング層２００ｂと同様、Ａｕ、Ａｌまたはこれらの金属の少なくも一種を含む合金からなることが好ましい。ＡｕおよびＡｌはボンディングボールとして使用されることが多い金ボールとの密着性の良い金属なので、Ａｕ、Ａｌまたはこれらの金属の少なくも一種を含む合金を用いることにより、ボンディングワイヤとの密着性に優れたものとすることができる。中でも、特に望ましいのはＡｕである。
　また、第２のボンディング層２３０ｂの厚みは、５００オングストローム以上２００００オングストローム以下の範囲であることが好ましく、更に望ましくは５０００オングストローム以上１５０００オングストローム以下である。
　第２のボンディング層２３０ｂが薄すぎるとボンディングボールとの密着性が悪くなり、厚すぎても特に利点は生ぜず、コスト増大を招くのみである。 <Second bonding layer>
Like the first bonding layer 200b, the second bonding layer 230b shown in FIG. 1 is preferably made of Au, Al, or an alloy containing at least one of these metals. Since Au and Al are metals with good adhesion to gold balls that are often used as bonding balls, the use of Au, Al or an alloy containing at least one of these metals improves adhesion to bonding wires. It can be excellent. Of these, Au is particularly desirable.
The thickness of the second bonding layer 230b is preferably in the range of 500 angstroms or more and 20000 angstroms or less, and more preferably 5000 angstroms or more and 15000 angstroms or less.
If the second bonding layer 230b is too thin, the adhesion to the bonding ball is deteriorated. If the second bonding layer 230b is too thick, no particular advantage is produced and only the cost is increased.
　第２の接合層２２０およびこれに積層される第２のボンディングパッド電極２３０は、ｎコンタクト層１４０ａの半導体層露出面１４０ｃの上であれば、どこへでも形成することができる。ただし、ボンディング作業のしやすさという観点からは、ボンディングボールの直径よりもわずかに大きい程度が好ましく、直径１００μｍの円形程度であることが一般的である。 The second bonding layer 220 and the second bonding pad electrode 230 laminated thereon can be formed anywhere as long as it is on the semiconductor layer exposed surface 140c of the n contact layer 140a. However, from the viewpoint of ease of bonding work, it is preferably slightly larger than the diameter of the bonding ball, and is generally circular with a diameter of 100 μm.
　なお、本実施の形態では、後述するように、第１の接合層１９０と第２の接合層２２０とが同一のプロセスにおいて形成され、また、第１のボンディングパッド電極２００と第２のボンディングパッド電極２３０とが同一のプロセスにおいて形成される。このため、第１の接合層１９０と第２の接合層２２０とが同じ構成を有しており、第１のボンディングパッド電極２００と第２のボンディングパッド電極２３０とが同じ構成を有している。 In this embodiment, as described later, the first bonding layer 190 and the second bonding layer 220 are formed in the same process, and the first bonding pad electrode 200 and the second bonding pad are formed. The electrode 230 is formed in the same process. Therefore, the first bonding layer 190 and the second bonding layer 220 have the same configuration, and the first bonding pad electrode 200 and the second bonding pad electrode 230 have the same configuration. .
（半導体発光素子の製造方法）
　次に、図１に示す半導体発光素子１の製造方法の一例について説明する。
　本実施形態における半導体発光素子１の製造方法は、基板１１０上に、発光層１５０を含む積層半導体層１００を形成する工程と、積層半導体層１００の一部を切り欠けて半導体層露出面１４０ｃを形成する工程と、積層半導体層１００の上面１６０ｃに第１の電極２１０を形成し且つ半導体層露出面１４０ｃに第２の電極２４０を形成する電極形成工程とを有している。 (Manufacturing method of semiconductor light emitting device)
Next, an example of a manufacturing method of the semiconductor light emitting device 1 shown in FIG. 1 will be described.
In the method for manufacturing the semiconductor light emitting device 1 according to the present embodiment, the step of forming the laminated semiconductor layer 100 including the light emitting layer 150 on the substrate 110 and the semiconductor layer exposed surface 140c by cutting out part of the laminated semiconductor layer 100 are formed. Forming the first electrode 210 on the upper surface 160c of the stacked semiconductor layer 100, and forming the second electrode 240 on the exposed surface 140c of the semiconductor layer.
　ここで、発光層１５０を含む積層半導体層１００を形成する工程は、中間層１２０を形成する中間層形成工程、下地層１３０を形成する下地層形成工程、ｎ型半導体層１４０を形成するｎ型半導体層形成工程、発光層１５０を形成する発光層形成工程、ｐ型半導体層１６０を形成するｐ型半導体層形成工程を有している。さらに、電極形成工程では、積層半導体層１００の上面１６０ｃに透明電極１７０を形成する透明電極形成工程、透明電極１７０上に第１の接合層１９０を形成するとともに半導体層露出面１４０ｃ上に第２の接合層２２０を形成する接合層形成工程、第１の接合層１９０上に第１のバリア層２００ａを形成するとともに第２の接合層２２０上に第２のバリア層２３０ａを形成するバリア層形成工程、第１のバリア層２００ａ上に第１のボンディング層２００ｂを形成するとともに第２のバリア層２３０ａ上に第２のボンディング層２３０ｂを形成するボンディング層形成工程を有している。 Here, the step of forming the laminated semiconductor layer 100 including the light emitting layer 150 includes an intermediate layer forming step for forming the intermediate layer 120, an underlayer forming step for forming the underlayer 130, and an n-type for forming the n-type semiconductor layer 140. A semiconductor layer forming step, a light emitting layer forming step for forming the light emitting layer 150, and a p type semiconductor layer forming step for forming the p type semiconductor layer 160. Further, in the electrode forming step, a transparent electrode forming step for forming the transparent electrode 170 on the upper surface 160c of the laminated semiconductor layer 100, a first bonding layer 190 is formed on the transparent electrode 170, and a second on the semiconductor layer exposed surface 140c. A bonding layer forming step of forming the bonding layer 220, and a barrier layer formation in which the first barrier layer 200a is formed on the first bonding layer 190 and the second barrier layer 230a is formed on the second bonding layer 220 And a bonding layer forming step of forming the first bonding layer 200b on the first barrier layer 200a and forming the second bonding layer 230b on the second barrier layer 230a.
　さらに、本実施の形態が適用される半導体発光素子１の製造方法は、必要に応じて、電極形成工程の後、得られた半導体発光素子に熱処理を施すアニール工程をさらに有している場合がある。 Furthermore, the method for manufacturing the semiconductor light emitting device 1 to which the present embodiment is applied may further include an annealing step for performing a heat treatment on the obtained semiconductor light emitting device after the electrode forming step, if necessary. is there.
　以下、各工程について、順番に説明する。
＜積層半導体層形成工程＞
　積層半導体層形成工程は、中間層形成工程と、下地層形成工程と、ｎ型半導体層形成工程と、発光層形成工程と、ｐ型半導体層形成工程とからなる。
＜中間層形成工程＞
　先ず、サファイア基板等の基板１１０を用意し、前処理を施す。前処理としては、例えば、スパッタ装置のチャンバ内に基板１１０を配置し、中間層１２０を形成する前にスパッタするなどの方法によって行うことができる。具体的には、チャンバ内において、基板１１０をＡｒやＮ2のプラズマ中に曝す事によって上面を洗浄する前処理を行なってもよい。ＡｒガスやＮ2ガスなどのプラズマを基板１１０に作用させることで、基板１１０の上面に付着した有機物や酸化物を除去することができる。 Hereinafter, each process is demonstrated in order.
<Laminated semiconductor layer forming step>
The laminated semiconductor layer forming step includes an intermediate layer forming step, a base layer forming step, an n-type semiconductor layer forming step, a light emitting layer forming step, and a p-type semiconductor layer forming step.
<Intermediate layer forming step>
First, a substrate 110 such as a sapphire substrate is prepared and subjected to pretreatment. The pretreatment can be performed by, for example, a method in which the substrate 110 is placed in a chamber of a sputtering apparatus and sputtering is performed before the intermediate layer 120 is formed. Specifically, pretreatment for cleaning the upper surface may be performed by exposing the substrate 110 to Ar or N 2 plasma in the chamber. By causing plasma such as Ar gas or N 2 gas to act on the substrate 110, organic substances and oxides attached to the upper surface of the substrate 110 can be removed.
　次に、基板１１０の上面に、スパッタ法によって、中間層１２０を積層する。
　スパッタ法によって、単結晶構造を有する中間層１２０を形成する場合、チャンバ内の窒素原料と不活性ガスの流量に対する窒素流量の比を、窒素原料が５０％～１００％、望ましくは７５％となるようにすることが望ましい。
　また、スパッタ法によって、柱状結晶（多結晶）を有する中間層１２０を形成する場合、チャンバ内の窒素原料と不活性ガスの流量に対する窒素流量の比を、窒素原料が１％～５０％、望ましくは２５％となるようにすることが望ましい。なお、中間層１２０は、上述したスパッタ法だけでなく、ＭＯＣＶＤ法で形成することもできる。 Next, the intermediate layer 120 is stacked on the upper surface of the substrate 110 by sputtering.
When the intermediate layer 120 having a single crystal structure is formed by sputtering, the ratio of the nitrogen flow rate to the nitrogen source flow rate in the chamber and the flow rate of the inert gas is 50% to 100%, preferably 75%. It is desirable to do so.
When the intermediate layer 120 having columnar crystals (polycrystal) is formed by sputtering, the ratio of the nitrogen flow rate to the nitrogen source flow rate in the chamber and the flow rate of the inert gas is preferably 1% to 50% for the nitrogen source. Is preferably 25%. Note that the intermediate layer 120 can be formed not only by the sputtering method described above but also by the MOCVD method.
＜下地層形成工程＞
　次に、中間層１２０を形成した後、中間層１２０が形成された基板１１０の上面に、単結晶の下地層１３０を形成する。下地層１３０は、スパッタ法で形成してもよく、ＭＯＣＶＤ法で形成してもよい。 <Underlayer formation process>
Next, after forming the intermediate layer 120, a single crystal base layer 130 is formed on the upper surface of the substrate 110 on which the intermediate layer 120 is formed. The underlayer 130 may be formed by sputtering or MOCVD.
＜ｎ型半導体層形成工程＞
　下地層１３０の形成後、ｎコンタクト層１４０ａ及びｎクラッド層１４０ｂを積層してｎ型半導体層１４０を形成する。ｎコンタクト層１４０ａ及びｎクラッド層１４０ｂは、スパッタ法で形成してもよく、ＭＯＣＶＤ法で形成してもよい。 <N-type semiconductor layer forming step>
After forming the base layer 130, the n-type semiconductor layer 140 is formed by laminating the n-contact layer 140a and the n-cladding layer 140b. The n contact layer 140a and the n clad layer 140b may be formed by a sputtering method or an MOCVD method.
＜発光層形成工程＞
　発光層１５０の形成は、スパッタ法、ＭＯＣＶＤ法のいずれの方法でもよいが、特にＭＯＣＶＤ法が好ましい。具体的には、障壁層１５０ａと井戸層１５０ｂとを交互に繰り返して積層し、且つ、ｎ型半導体層１４０側及びｐ型半導体層１６０側に障壁層１５０ａが配される順で積層すればよい。 <Light emitting layer forming step>
The light emitting layer 150 can be formed by either sputtering or MOCVD, but MOCVD is particularly preferable. Specifically, the barrier layers 150a and the well layers 150b are alternately and repeatedly stacked, and the barrier layers 150a may be stacked in the order in which the barrier layers 150a are disposed on the n-type semiconductor layer 140 side and the p-type semiconductor layer 160 side. .
＜ｐ型半導体層形成工程＞
　また、ｐ型半導体層１６０の形成は、スパッタ法、ＭＯＣＶＤ法のいずれの方法でもよい。具体的には、ｐクラッド層１６０ａと、ｐコンタクト層１６０ｂとを順次積層すればよい。 <P-type semiconductor layer forming step>
In addition, the p-type semiconductor layer 160 may be formed by either a sputtering method or an MOCVD method. Specifically, the p-clad layer 160a and the p-contact layer 160b may be sequentially stacked.
＜半導体層露出面形成工程＞
　透明電極１７０の形成に先立ち、公知のフォトリソグラフィーの手法によってパターニングして、所定の領域の積層半導体層１００の一部をエッチングしてｎコンタクト層１４０ａの一部を露出させ、半導体層露出面１４０ｃを形成させる。 <Semiconductor layer exposed surface forming step>
Prior to the formation of the transparent electrode 170, patterning is performed by a known photolithography technique, and a part of the laminated semiconductor layer 100 in a predetermined region is etched to expose a part of the n contact layer 140a, thereby exposing the semiconductor layer exposed surface 140c. To form.
＜電極形成工程＞
　電極形成工程は、透明電極形成工程と、接合層形成工程と、バリア層形成工程と、ボンディング層形成工程とからなる。
＜透明電極形成工程＞
　マスクで半導体層露出面１４０ｃをカバーして、エッチング除去せずに残したｐ型半導体層１６０上に、スパッタ法などの公知の方法を用いて、透明電極１７０を形成する。
　なお、ｐ型半導体層１６０上に先に透明電極１７０を形成した後、透明電極１７０を形成した状態で、所定の領域の透明電極１７０および積層半導体層１００の一部をエッチングすることで半導体層露出面１４０ｃを形成するようにしてもよい。 <Electrode formation process>
The electrode forming process includes a transparent electrode forming process, a bonding layer forming process, a barrier layer forming process, and a bonding layer forming process.
<Transparent electrode formation process>
The transparent electrode 170 is formed on the p-type semiconductor layer 160 that is left without being removed by etching by covering the semiconductor layer exposed surface 140c with a mask, using a known method such as sputtering.
In addition, after forming the transparent electrode 170 on the p-type semiconductor layer 160 in advance, the transparent electrode 170 in a predetermined region and a part of the laminated semiconductor layer 100 are etched to form the semiconductor layer. The exposed surface 140c may be formed.
　そして、透明電極１７０および半導体層露出面１４０ｃの上面にＳｉＯ2からなる保護層１８０を形成した後、保護層１８０上に図示しないレジストを塗布する。
　そして、第１のボンディングパッド電極２００および第２のボンディングパッド電極２３０をそれぞれ形成する部分に対応する部位のレジストを公知の手法によって除去することで、ｐ型半導体層１６０上に形成された保護層１８０の一部および半導体層露出面１４０ｃ上に形成された保護層１８０の一部をそれぞれ外側に露出させる。
　そして、透明電極１７０の上面に垂直な方向よりＳｉＯ2からなる保護層１８０のＲＩＥ（反応性イオンエッチング）を行い、第１のボンディングパッド電極２００および第２のボンディングパッド電極２３０を形成する部分に対応する部位の保護層１８０を除去して、透明電極１７０の一部およびｎコンタクト層１４０ａの一部の上面を露出させる。 Then, after forming a protective layer 180 made of SiO 2 on the transparent electrode 170 and the semiconductor layer exposed surface 140c, a resist (not shown) is applied on the protective layer 180.
A protective layer formed on the p-type semiconductor layer 160 is then removed by removing the resist at portions corresponding to the portions where the first bonding pad electrode 200 and the second bonding pad electrode 230 are to be formed. Part of 180 and part of protective layer 180 formed on semiconductor layer exposed surface 140c are exposed to the outside.
Then, RIE (reactive ion etching) of the protective layer 180 made of SiO 2 is performed in a direction perpendicular to the upper surface of the transparent electrode 170 to form the first bonding pad electrode 200 and the second bonding pad electrode 230. The protective layer 180 at the corresponding portion is removed, and a part of the transparent electrode 170 and a part of the upper surface of the n contact layer 140a are exposed.
＜接合層形成工程＞
　次に、スパッタ法により、透明電極１７０の露出面上に第１の接合層１９０を形成するとともに、半導体層露出面１４０ｃの露出面に第２の接合層２２０を形成する。 <Joint layer forming step>
Next, the first bonding layer 190 is formed on the exposed surface of the transparent electrode 170 by sputtering, and the second bonding layer 220 is formed on the exposed surface of the semiconductor layer exposed surface 140c.
　では最初に、接合層形成工程において、バルブメタルの窒化物の層を形成する場合について説明する。
　この場合、接合層形成工程では、バルブメタルの窒化物の層が透明電極１７０および半導体層露出面１４０ｃと接するように製膜を行う。ここで、スパッタ法を用い、バルブメタルの窒化膜を形成する手法としては、例えばバルブメタルからなる金属ターゲットを用い、窒素を含む雰囲気下においてスパッタを行う方法が挙げられる。ここで、スパッタの雰囲気としては、不活性ガスに対して３．０体積％以上５０体積％以下、より好ましくは５．０体積％以上１５体積％以下の窒素が存在していることが好ましい。このとき、例えば第１の接合層１９０の透明電極１７０側および第２の接合層２２０の半導体層露出面１４０ｃ側をバルブメタル窒化物層とし、第１の接合層１９０の第１のバリア層２００ａ側および第２の接合層２２０の第２のバリア層２３０ａ側をバルブメタル層とする場合には、接合層形成工程の初期における窒素濃度を高くし、接合層形成工程の終期における窒素濃度を初期よりも低くあるいは窒素供給を停止するようにすればよい。また、バルブメタルの窒化膜を形成する他の手法としては、例えばバルブメタル窒化物からなる金属窒化物ターゲットを用い、窒素を含む雰囲気下あるいは窒素を含まない雰囲気下においてスパッタを行う方法が挙げられる。このとき、スパッタ条件を制御したスパッタ法を用いることにより、スパッタ材料によらず、カバレッジ性を高くして第１の接合層１９０および第２の接合層２２０を成膜することができる。なお、このとき、透明電極１７０上および半導体層露出面１４０ｃ上に残存するレジストの硬化部にも第１の接合層１９０および第２の接合層２２０と同じ材料が積層される。 First, a case where a valve metal nitride layer is formed in the bonding layer forming step will be described.
In this case, in the bonding layer forming step, film formation is performed so that the nitride layer of the valve metal is in contact with the transparent electrode 170 and the semiconductor layer exposed surface 140c. Here, as a method of forming a valve metal nitride film using a sputtering method, for example, there is a method of performing sputtering in an atmosphere containing nitrogen using a metal target made of valve metal. Here, as an atmosphere of sputtering, it is preferable that nitrogen of 3.0 volume% or more and 50 volume% or less, more preferably 5.0 volume% or more and 15 volume% or less is present with respect to the inert gas. At this time, for example, the transparent electrode 170 side of the first bonding layer 190 and the semiconductor layer exposed surface 140c side of the second bonding layer 220 are valve metal nitride layers, and the first barrier layer 200a of the first bonding layer 190 is formed. When the side and the second barrier layer 230a side of the second bonding layer 220 are valve metal layers, the nitrogen concentration at the initial stage of the bonding layer forming process is increased, and the nitrogen concentration at the end of the bonding layer forming process is set to the initial value. Or the nitrogen supply may be stopped. Another method for forming a valve metal nitride film is, for example, a method in which sputtering is performed in a nitrogen-containing atmosphere or a nitrogen-free atmosphere using a metal nitride target made of valve metal nitride. . At this time, by using a sputtering method in which sputtering conditions are controlled, the first bonding layer 190 and the second bonding layer 220 can be formed with high coverage regardless of the sputtering material. At this time, the same material as that of the first bonding layer 190 and the second bonding layer 220 is also laminated on the cured portion of the resist remaining on the transparent electrode 170 and the semiconductor layer exposed surface 140c.
　次に、接合層形成工程において、バルブメタルの酸化物の層を形成する場合について説明する。
　この場合、接合層形成工程では、バルブメタルの酸化物の層が透明電極１７０および半導体層露出面１４０ｃと接するように製膜を行う。ここで、スパッタ法を用い、バルブメタルの酸化膜を形成する手法としては、例えばバルブメタルからなる金属ターゲットを用い、酸素を含む雰囲気下においてスパッタを行う方法が挙げられる。ここで、スパッタの雰囲気としては、アルゴンに対して０．１体積％以上１５体積％以下、より好ましくは１．０体積％以上１０体積％以下の酸素が存在していることが好ましい。このとき、例えば第１の接合層１９０の透明電極１７０側および第２の接合層２２０の半導体層露出面１４０ｃ側をバルブメタル酸化物層とし、第１の接合層１９０の第１のバリア層２００ａ側および第２の接合層２２０の第２のバリア層２３０ａ側をバルブメタル層とする場合には、接合層形成工程の初期における酸素濃度を高くし、接合層形成工程の終期における酸素濃度を初期よりも低くあるいは酸素供給を停止するようにすればよい。また、バルブメタルの酸化膜を形成する他の手法としては、例えばバルブメタル酸化物からなる金属酸化物ターゲットを用い、酸素を含む雰囲気下あるいは酸素を含まない雰囲気下においてスパッタを行う方法が挙げられる。このとき、スパッタ条件を制御したスパッタ法を用いることにより、スパッタ材料によらず、カバレッジ性を高くして第１の接合層１９０および第２の接合層２２０を成膜することができる。なお、このとき、透明電極１７０上および半導体層露出面１４０ｃ上に残存するレジストの硬化部にも第１の接合層１９０および第２の接合層２２０と同じ材料が積層される。 Next, the case where a valve metal oxide layer is formed in the bonding layer forming step will be described.
In this case, in the bonding layer forming step, film formation is performed such that the oxide layer of the valve metal is in contact with the transparent electrode 170 and the semiconductor layer exposed surface 140c. Here, as a method of forming a valve metal oxide film using a sputtering method, for example, a method of performing sputtering in an atmosphere containing oxygen using a metal target made of valve metal can be cited. Here, as an atmosphere of sputtering, it is preferable that 0.1 volume% or more and 15 volume% or less, more preferably 1.0 volume% or more and 10 volume% or less of oxygen is present with respect to argon. At this time, for example, the transparent electrode 170 side of the first bonding layer 190 and the semiconductor layer exposed surface 140c side of the second bonding layer 220 are valve metal oxide layers, and the first barrier layer 200a of the first bonding layer 190 is formed. When the side and the second barrier layer 230a side of the second bonding layer 220 are valve metal layers, the oxygen concentration at the initial stage of the bonding layer forming step is increased, and the oxygen concentration at the end of the bonding layer forming step is set to the initial value. Or the oxygen supply may be stopped. Another method for forming the valve metal oxide film is, for example, a method in which sputtering is performed in an oxygen-containing atmosphere or an oxygen-free atmosphere using a metal oxide target made of valve metal oxide. . At this time, by using a sputtering method in which sputtering conditions are controlled, the first bonding layer 190 and the second bonding layer 220 can be formed with high coverage regardless of the sputtering material. At this time, the same material as that of the first bonding layer 190 and the second bonding layer 220 is also laminated on the cured portion of the resist remaining on the transparent electrode 170 and the semiconductor layer exposed surface 140c.
＜バリア層形成工程＞
　続いて、スパッタ法により、第１の接合層１９０上に第１のバリア層２００ａを形成するとともに、第２の接合層２２０上に第２のバリア層２３０ａを形成する。このとき、スパッタ条件を制御したスパッタ法を用いることにより、スパッタ材料によらず、カバレッジ性を高くして、第１のバリア層２００ａおよび第２のバリア層２３０ａを成膜することができる。なお、このとき、透明電極１７０上および半導体層露出面１４０ｃ上に残存するレジストの硬化部側にも第１のバリア層２００ａおよび第２のバリア層２３０ａと同じ材料が積層される。 <Barrier layer formation process>
Subsequently, the first barrier layer 200a is formed on the first bonding layer 190 and the second barrier layer 230a is formed on the second bonding layer 220 by sputtering. At this time, by using a sputtering method in which sputtering conditions are controlled, the first barrier layer 200a and the second barrier layer 230a can be formed with high coverage regardless of the sputtering material. At this time, the same material as that of the first barrier layer 200a and the second barrier layer 230a is laminated also on the cured portion side of the resist remaining on the transparent electrode 170 and the semiconductor layer exposed surface 140c.
＜ボンディング層形成工程＞
　さらに、スパッタ法により、第１のバリア層２００ａ上に第１のボンディング層２００ｂを形成するとともに、第２のバリア層２３０ａ上に第２のボンディング層２３０ｂを形成する。このとき、スパッタ条件を制御したスパッタ法を用いることにより、スパッタ材料によらず、カバレッジ性を高くして、第１のボンディング層２００ｂおよび第２のボンディング層２３０ｂを成膜することができる。なお、このとき、透明電極１７０上および半導体層露出面１４０ｃ上に残存するレジストの硬化部側にも第１のボンディング層２００ｂおよび第２のボンディング層２３０ｂと同じ材料が積層される。 <Bonding layer formation process>
Further, the first bonding layer 200b is formed on the first barrier layer 200a and the second bonding layer 230b is formed on the second barrier layer 230a by sputtering. At this time, by using a sputtering method in which sputtering conditions are controlled, the first bonding layer 200b and the second bonding layer 230b can be formed with high coverage regardless of the sputtering material. At this time, the same material as that of the first bonding layer 200b and the second bonding layer 230b is also laminated on the cured portion side of the resist remaining on the transparent electrode 170 and the semiconductor layer exposed surface 140c.
　最後に、レジスト剥離液に浸漬することにより、レジストの硬化部を剥離する。これにより、透明電極１７０上には、第１の接合層１９０と第１のバリア層２００ａおよび第１のボンディング層２００ｂを有する第１のボンディングパッド電極２００とが形成される。また、ｎコンタクト層１４０ａ上には、第２の接合層２２０と第２のバリア層２３０ａおよび第２のボンディング層２３０ｂを有する第２のボンディングパッド電極２３０が形成される。 Finally, the hardened portion of the resist is peeled off by dipping in a resist stripping solution. As a result, the first bonding layer 190 and the first bonding pad electrode 200 having the first barrier layer 200a and the first bonding layer 200b are formed on the transparent electrode 170. A second bonding pad electrode 230 having a second bonding layer 220, a second barrier layer 230a, and a second bonding layer 230b is formed on the n contact layer 140a.
＜アニール工程＞
　そして、このようにして得られた半導体発光素子１を、例えば窒素などの還元雰囲気下において、１５０℃以上６００℃以下、より好ましくは２００℃以上５００℃以下でアニール処理する。このアニール工程は、第１の接合層１９０を介した透明電極１７０と第１のボンディングパッド電極２００との密着性、および、第２の接合層２２０を介した半導体層露出面１４０ｃと第２のボンディングパッド電極２３０との密着性を高めるために行われる。なお、アニール処理は必ずしも行う必要はないが、密着性を高めるためには行う方がより好ましい。 <Annealing process>
Then, the semiconductor light emitting device 1 obtained in this way is annealed at 150 ° C. or higher and 600 ° C. or lower, more preferably 200 ° C. or higher and 500 ° C. or lower in a reducing atmosphere such as nitrogen. In this annealing step, the adhesiveness between the transparent electrode 170 and the first bonding pad electrode 200 via the first bonding layer 190, and the semiconductor layer exposed surface 140c via the second bonding layer 220 and the second bonding layer 220 are exposed. This is performed in order to improve the adhesion with the bonding pad electrode 230. Note that the annealing treatment is not necessarily performed, but it is more preferable to perform the annealing treatment in order to improve the adhesion.
　このように、上述した半導体発光素子１の製造方法においては、接合層製造工程において、第１の接合層１９０と透明電極１７０との接触面側、および、第２の接合層２２０と半導体層露出面１４０ｃとの接触面側にバルブメタルの窒化膜を形成する例について説明を行ったが、これらに限られない。
　具体的に説明すると、例えば透明電極形成工程においてｐ型半導体層１６０上に透明電極１７０を形成し、得られた透明電極１７０を窒素プラズマ中に曝す窒素プラズマ処理を行ってから、窒素プラズマ処理がなされた透明電極１７０上に保護層１８０を形成するようにしてもよい。なお、保護層１８０を形成した後、上述した接合層形成工程、バリア層形成工程およびボンディング層形成工程を行うことで、半導体発光素子１を得ることができる。 Thus, in the manufacturing method of the semiconductor light emitting element 1 described above, in the bonding layer manufacturing step, the contact surface side between the first bonding layer 190 and the transparent electrode 170 and the second bonding layer 220 and the semiconductor layer exposed. Although an example of forming a valve metal nitride film on the contact surface side with the surface 140c has been described, the present invention is not limited thereto.
Specifically, for example, in the transparent electrode forming step, the transparent electrode 170 is formed on the p-type semiconductor layer 160, and the obtained transparent electrode 170 is exposed to nitrogen plasma. The protective layer 180 may be formed on the transparent electrode 170 made. In addition, after forming the protective layer 180, the semiconductor light-emitting device 1 can be obtained by performing the above-described bonding layer forming step, barrier layer forming step, and bonding layer forming step.
　また、上述した半導体発光素子１の製造方法においては、接合層製造工程において、第１の接合層１９０と透明電極１７０との接触面側、および、第２の接合層２２０と半導体層露出面１４０ｃとの接触面側にバルブメタルの酸化物膜を形成する例について説明を行ったが、これらに限られない。
　具体的に説明すると、例えば透明電極形成工程においてｐ型半導体層１６０上に透明電極１７０を形成し、得られた透明電極１７０を酸素プラズマ中に曝す酸素プラズマ処理を行ってから、酸素プラズマ処理がなされた透明電極１７０上に保護層１８０を形成するようにしてもよい。なお、保護層１８０を形成した後、上述した接合層形成工程、バリア層形成工程およびボンディング層形成工程を行うことで、半導体発光素子１を得ることができる。 Moreover, in the manufacturing method of the semiconductor light emitting element 1 described above, in the bonding layer manufacturing step, the contact surface side between the first bonding layer 190 and the transparent electrode 170, and the second bonding layer 220 and the semiconductor layer exposed surface 140c. Although an example in which an oxide film of a valve metal is formed on the contact surface side of the valve has been described, it is not limited thereto.
More specifically, for example, in the transparent electrode forming step, the transparent electrode 170 is formed on the p-type semiconductor layer 160, and the oxygen plasma treatment is performed after the obtained transparent electrode 170 is exposed to oxygen plasma. The protective layer 180 may be formed on the transparent electrode 170 made. In addition, after forming the protective layer 180, the semiconductor light-emitting device 1 can be obtained by performing the above-described bonding layer forming step, barrier layer forming step, and bonding layer forming step.
　このように透明電極１７０に酸素プラズマ処理を行った場合は、酸素プラズマ処理を行わなかった場合と比較して、透明電極１７０中により多くの酸素が取り込まれることになる。このような過剰な酸素は、後段の接合層形成工程、バリア層形成工程およびボンディング層形成工程において透明電極１７０が加熱された際に第１の接合層１９０に取り込まれ、第１の接合層１９０の透明電極１７０側のバルブメタルを酸化させる。また、透明電極１７０から第１の接合層１９０に移動する酸素は、基本的に透明電極１７０内において過剰な酸素であるため、透明電極１７０の特性もほとんど変わらない。したがって、接合層形成工程において透明電極１７０側にバルブメタルの酸化物膜を形成する場合と同様の結果が得られる。 Thus, when oxygen plasma treatment is performed on the transparent electrode 170, more oxygen is taken into the transparent electrode 170 than when oxygen plasma treatment is not performed. Such excess oxygen is taken into the first bonding layer 190 when the transparent electrode 170 is heated in the subsequent bonding layer forming step, barrier layer forming step, and bonding layer forming step, and the first bonding layer 190 The valve metal on the transparent electrode 170 side is oxidized. In addition, since the oxygen moving from the transparent electrode 170 to the first bonding layer 190 is basically excess oxygen in the transparent electrode 170, the characteristics of the transparent electrode 170 are hardly changed. Therefore, the same result as that in the case where the valve metal oxide film is formed on the transparent electrode 170 side in the bonding layer forming step can be obtained.
　本実施の形態では、透明電極１７０と第１のボンディングパッド電極２００とを、バルブメタルの窒化物または酸化物の少なくともいずれか一方を含む第１の接合層１９０を介して接続するようにしたので、透明電極１７０に対する第１のボンディングパッド電極２００の密着性および接続強度を向上させることができる。 In the present embodiment, the transparent electrode 170 and the first bonding pad electrode 200 are connected via the first bonding layer 190 containing at least one of a nitride or an oxide of valve metal. The adhesion and connection strength of the first bonding pad electrode 200 to the transparent electrode 170 can be improved.
　また、本実施の形態では、ｎ型半導体層１４０のｎコンタクト層１４０ａと第２のボンディングパッド電極２３０とを、バルブメタルの窒化物または酸化物の少なくともいずれか一方を含む第２の接合層２２０を介して接続するようにしたので、ｎコンタクト層１４０ａと第２のボンディングパッド電極２３０との密着性および接続強度を高めることができる。 In the present embodiment, the n-contact layer 140a of the n-type semiconductor layer 140 and the second bonding pad electrode 230 are replaced with a second bonding layer 220 containing at least one of a valve metal nitride and an oxide. Therefore, the adhesion and connection strength between the n contact layer 140a and the second bonding pad electrode 230 can be increased.
　さらに、本実施の形態では、第１の接続層１９０および第２の接続層２２０を同じバルブメタルの窒化物または酸化物の少なくともいずれか一方を含むように構成することで、第１の接続層１９０および第２の接続層２２０を同時に作製することが可能となり、半導体発光素子１の生産性を向上させることができる。 Furthermore, in the present embodiment, the first connection layer 190 and the second connection layer 220 are configured to include at least one of nitride and oxide of the same valve metal, so that the first connection layer 190 and the second connection layer 220 can be manufactured at the same time, and the productivity of the semiconductor light emitting device 1 can be improved.
　さらにまた、本実施の形態では、第１の接続層１９０上に形成される第１のボンディングパッド電極２００および第２の接続層２２０上に形成される第２のボンディングパッド電極２３０を、同じ構成とすることで、第１のボンディングパッド電極２００および第２のボンディングパッド電極２３０を同時に作成することが可能となり、半導体発光素子１の生産性を向上させることができる。 Furthermore, in this embodiment, the first bonding pad electrode 200 formed on the first connection layer 190 and the second bonding pad electrode 230 formed on the second connection layer 220 have the same configuration. By doing so, the first bonding pad electrode 200 and the second bonding pad electrode 230 can be formed simultaneously, and the productivity of the semiconductor light emitting device 1 can be improved.
　では次に、本発明の実施例について説明を行うが、本発明は実施例に限定されない。 Next, examples of the present invention will be described, but the present invention is not limited to the examples.
＜第１の実施例＞
　本発明者は、各種製造条件を組み合わせて図１に示す半導体発光素子１の製造を行い、第１の電極２１０における透明電極１７０と第１のボンディングパッド電極２００との密着性について、公知なテープ剥離試験（テープ試験）に基づき検討を行った。なお、透明電極１７０と第１のボンディングパッド電極２００との密着性には、透明電極１７０と第１の接合層１９０との密着性および第１の接合層１９０と第１のボンディングパッド電極２００における第１のバリア層２００ａとの密着性が大きく影響している。 <First embodiment>
The inventor manufactures the semiconductor light emitting device 1 shown in FIG. 1 by combining various manufacturing conditions, and a known tape for the adhesion between the transparent electrode 170 and the first bonding pad electrode 200 in the first electrode 210. The examination was performed based on a peel test (tape test). The adhesion between the transparent electrode 170 and the first bonding pad electrode 200 includes the adhesion between the transparent electrode 170 and the first bonding layer 190 and the adhesion between the first bonding layer 190 and the first bonding pad electrode 200. Adhesion with the first barrier layer 200a has a great influence.
　図４は、実施例１～１５および比較例１～６における各種製造条件と、各々の評価結果との関係を示している。
　ここで、図４には、製造条件として、接合層形成工程におけるスパッタのターゲット材（接合層金属）およびスパッタにおける雰囲気への酸素導入の有無と、透明電極１７０に対する酸素プラズマ処理の有無と、アニール工程すなわちアニール処理の有無とを記載している。なお、ここでは、透明電極１７０としてＩＺＯ膜を用いた。
　また、図４には、評価項目として、第１の電極２１０における透明電極１７０と第１のボンディングパッド電極２００との密着性をＡ～Ｄの４ランクで示した。なお、評価「Ａ」は「良」、評価［Ｂ］はやや良、評価「Ｃ」は「やや不良」、そして評価「Ｄ」は「不良」を、それぞれ意味している。 FIG. 4 shows the relationship between various manufacturing conditions in Examples 1 to 15 and Comparative Examples 1 to 6 and the respective evaluation results.
Here, in FIG. 4, as manufacturing conditions, the sputtering target material (bonding layer metal) in the bonding layer forming step and the presence or absence of oxygen introduction into the atmosphere in the sputtering, the presence or absence of oxygen plasma treatment on the transparent electrode 170, annealing The process, that is, the presence or absence of annealing treatment is described. Here, an IZO film was used as the transparent electrode 170.
In FIG. 4, as an evaluation item, the adhesion between the transparent electrode 170 and the first bonding pad electrode 200 in the first electrode 210 is shown in four ranks A to D. The evaluation “A” means “good”, the evaluation [B] means slightly good, the evaluation “C” means “slightly bad”, and the evaluation “D” means “bad”.
　実施例１～５および比較例１、２では、第１の接合層１９０を形成するためのスパッタのターゲット材としてＴａターゲットを用いた。また、実施例６～１０および比較例３、４では、第１の接合層１９０を形成するためのスパッタのターゲット材としてＮｂターゲットを用いた。さらに、実施例１１～１５および比較例５、６では、第１の接合層１９０を形成するためのスパッタのターゲット材としてＴｉターゲットを用いた。
　なお、実施例１～１５および比較例１～６において、第１のバリア層２００ａをＰｔで、第１のボンディング層２００ｂをＡｕで、それぞれ作製した。 In Examples 1 to 5 and Comparative Examples 1 and 2, a Ta target was used as a sputtering target material for forming the first bonding layer 190. In Examples 6 to 10 and Comparative Examples 3 and 4, an Nb target was used as a sputtering target material for forming the first bonding layer 190. Further, in Examples 11 to 15 and Comparative Examples 5 and 6, a Ti target was used as a sputtering target material for forming the first bonding layer 190.
In Examples 1 to 15 and Comparative Examples 1 to 6, the first barrier layer 200a was made of Pt, and the first bonding layer 200b was made of Au.
　次に、評価結果について説明する。
　実施例１～１５においては、いずれも密着性の評価がＡまたはＢとなった。すなわち、接合層形成工程においてスパッタの雰囲気に酸素を導入するか、あるいは、透明電極１７０の形成後に酸素プラズマ処理を行うかによって、透明電極１７０と第１のボンディングパッド電極２００との密着性が向上することが確認された。特に、酸素雰囲気下でスパッタを行って第１の接合層１９０を形成した後にアニール処理を施した実施例３、８、１３、および、これに加えてさらに透明電極１７０の酸素プラズマ処理を行った実施例５、１０、１５では、密着性の評価がＡとなった。 Next, the evaluation result will be described.
In each of Examples 1 to 15, the evaluation of adhesion was A or B. That is, the adhesion between the transparent electrode 170 and the first bonding pad electrode 200 is improved depending on whether oxygen is introduced into the sputtering atmosphere in the bonding layer forming step or the oxygen plasma treatment is performed after the transparent electrode 170 is formed. Confirmed to do. In particular, Examples 3, 8, and 13 in which the first bonding layer 190 was formed by sputtering in an oxygen atmosphere and then annealed, and in addition to this, oxygen plasma treatment of the transparent electrode 170 was performed. In Examples 5, 10, and 15, the evaluation of adhesion was A.
　一方、比較例１～６においては、いずれも密着性の評価がＣまたはＤとなった。すなわち、接合層形成工程においてスパッタの雰囲気に酸素を導入せず、しかも、透明電極１７０の形成後に酸素プラズマ処理を行わない場合には、透明電極１７０と第１のボンディングパッド電極２００との密着性が低下することが確認された。なお、アニール処理を行った比較例２、４、６については、アニール処理を行わない比較例１、３、５よりも密着性の向上がみられたが、良好と呼べるレベルには到達しなかった。 On the other hand, in each of Comparative Examples 1 to 6, the evaluation of adhesion was C or D. That is, when oxygen is not introduced into the sputtering atmosphere in the bonding layer forming step and oxygen plasma treatment is not performed after the transparent electrode 170 is formed, the adhesion between the transparent electrode 170 and the first bonding pad electrode 200 is improved. Was confirmed to decrease. In Comparative Examples 2, 4, and 6 that were annealed, adhesion was improved compared to Comparative Examples 1, 3, and 5 that were not annealed, but did not reach a level that could be called good. It was.
　ここで、図５は、実施例５の半導体発光素子１における第１の電極２１０を、Ｘ線光電子分光法（ＸＰＳ：X-ray Photoelectron Spectroscopy）の深さ分析によって解析した結果を示している。ただし、ここでは、透明電極１７０上に第１の接合層１９０を積層し、第１の接合層１９０上に第１のバリア層２００ａを積層したものを解析用の試料とした。
　図５において、横軸はＡｒガスを用いたスパッタリング時間であり、縦軸は各元素の原子濃度である。なお、スパッタリング時間は、第１の電極２１０の深さ方向の位置に対応している。 Here, FIG. 5 shows the result of analyzing the first electrode 210 in the semiconductor light emitting device 1 of Example 5 by depth analysis of X-ray photoelectron spectroscopy (XPS). However, here, a sample for analysis was obtained by laminating the first bonding layer 190 on the transparent electrode 170 and laminating the first barrier layer 200a on the first bonding layer 190.
In FIG. 5, the horizontal axis represents the sputtering time using Ar gas, and the vertical axis represents the atomic concentration of each element. Note that the sputtering time corresponds to the position of the first electrode 210 in the depth direction.
　図５から、スパッタリング時間が０～２００ｓｅｃの領域すなわち積層された透明電極１７０、第１の接合層１９０および第１のバリア層２００ａの最上部側においては、膜中に第１のバリア層２００ａを構成するＰｔが多く存在していることがわかる。
　また、スパッタリング時間が２００～１２００ｓｅｃの領域では、第１の接合層１９０を構成するＴａおよびＯが存在していること、すなわち、Ｔａの多くが酸化した状態で存在していることがわかる。
　次に、スパッタリング時間が１２００～３０００ｓｅｃの領域では、ＩｎとＺｎとＯとが存在し、ＩｎよりもＺｎの濃度が低いこと、すなわち、ＩＺＯの状態で存在していることがわかる。
　つまり、本実施の形態で説明した手法を用いて第１の接合層１９０を形成することで、バルブメタル（ここではＴａ）の酸化物が製膜され得ることが理解される。 From FIG. 5, in the region where the sputtering time is 0 to 200 sec, that is, on the uppermost side of the laminated transparent electrode 170, the first bonding layer 190, and the first barrier layer 200a, the first barrier layer 200a is formed in the film. It can be seen that a large amount of Pt exists.
It can also be seen that in the region where the sputtering time is 200 to 1200 sec, Ta and O constituting the first bonding layer 190 exist, that is, most of Ta exists in an oxidized state.
Next, it can be understood that In, Zn, and O exist in the region where the sputtering time is 1200 to 3000 seconds, and that the Zn concentration is lower than In, that is, exists in an IZO state.
That is, it is understood that an oxide of valve metal (here, Ta) can be formed by forming the first bonding layer 190 using the method described in this embodiment.
　また、図６は、実施例４の半導体発光素子１における第１の電極２１０の断面のＴＥＭ（Transmission Electron Microscope）写真を示している。ただし、ここでは、第１の電極２１０のうち、第１のボンディング層２００ｂを除く透明電極１７０、第１の接合層１９０および第１のバリア層２００ａのみを示している。なお、撮影においては、電子線の入射方向を、ＧａＮ［１０１０］とした。 FIG. 6 shows a TEM (Transmission Electron Microscope) photograph of the cross section of the first electrode 210 in the semiconductor light emitting device 1 of Example 4. However, only the transparent electrode 170 excluding the first bonding layer 200b, the first bonding layer 190, and the first barrier layer 200a of the first electrode 210 are shown here. In photographing, the incident direction of the electron beam was GaN [10 1 0].
　図６から、ＩＺＯからなる透明電極１７０とＰｔからなる第１のバリア層２００ａとの間に、ＩＺＯすなわち透明電極１７０側にＴａ酸化層が存在し且つＰｔすなわち第１のバリア層２００ａ側にＴａ金属層が存在する第１の接合層１９０が形成されていることがわかる。
　このように、本実施の形態で説明した手法を用いて第１の接合層１９０を形成することで、透明電極１７０側にバルブメタル（ここではＴａ）の酸化物、第１のバリア層２００ａ側にバルブメタルが製膜され得ることが理解される。 From FIG. 6, there is a Ta oxide layer on the IZO or transparent electrode 170 side between the transparent electrode 170 made of IZO and the first barrier layer 200a made of Pt, and Ta on the Pt or first barrier layer 200a side. It can be seen that the first bonding layer 190 in which the metal layer exists is formed.
In this manner, by forming the first bonding layer 190 using the method described in this embodiment, the oxide of the valve metal (here, Ta) is formed on the transparent electrode 170 side, and the first barrier layer 200a side is formed. It is understood that a valve metal can be formed.
　図５および図６に示したように、本実施の形態が適用される半導体発光素子１では、バルブメタルの酸化物によって第１の接合層１９０が構成されているが、この第１の接合層１９０は電極として使用するのに十分な電気伝導特性を有している。これは、第１の接合層１９０において、バルブメタルの酸化物が、例えばＴａの場合においてはＴａ2Ｏ5の形ではなく、Ｔａ2Ｏ5-xの導電体の形で存在していることに起因するものと考えられる。 As shown in FIGS. 5 and 6, in the semiconductor light emitting device 1 to which the present exemplary embodiment is applied, the first bonding layer 190 is configured by the valve metal oxide. 190 has sufficient electrical conduction characteristics to be used as an electrode. This is because, in the first bonding layer 190, the oxidation of the valve metal, for example in the case of Ta is that not in the form of Ta 2 O 5, are present in the form of conductor Ta 2 O 5-x It is thought to be caused by
＜第２の実施例＞
　本発明者は、各種製造条件を組み合わせて図１に示す半導体発光素子１の製造を行い、ｎコンタクト層１４０ａと第２のボンディングパッド電極２３０との間の導通状態すなわちオーミック特性について検討を行い、また、ｎコンタクト層１４０ａと第２のボンディングパッド電極２３０との密着性について、公知なテープ剥離試験（テープ試験）に基づき検討を行った。なお、ｎコンタクト層１４０ａと第２のボンディングパッド電極２３０との密着性には、ｎコンタクト層１４０ａと第２の接合層２２０との密着性および第２の接合層２２０と第２のボンディングパッド電極２３０における第２のバリア層２３０ａとの密着性が大きく影響している。 <Second Embodiment>
The inventor manufactures the semiconductor light emitting device 1 shown in FIG. 1 by combining various manufacturing conditions, examines the conduction state between the n contact layer 140a and the second bonding pad electrode 230, that is, ohmic characteristics, Further, the adhesion between the n-contact layer 140a and the second bonding pad electrode 230 was examined based on a known tape peeling test (tape test). Note that the adhesion between the n contact layer 140a and the second bonding pad electrode 230 includes the adhesion between the n contact layer 140a and the second bonding layer 220 and the second bonding layer 220 and the second bonding pad electrode. The adhesion between the second barrier layer 230a and the second barrier layer 230a is greatly affected.
　図７は、実施例１６～２１および比較例７～９における各種製造条件と、各々の評価結果との関係を示している。
　ここで、図７には、製造条件として、接合層形成工程におけるスパッタのターゲット材（接合層金属）と、スパッタにおける雰囲気への酸素導入の有無と、スパッタにおける雰囲気への窒素導入の有無とを記載している。
　また、図７には、評価項目として、ｎコンタクト層１４０ａおよび第２のボンディングパッド電極２３０間のオーミック特性と、ｎコンタクト層１４０ａと第２のボンディングパッド電極２３０との密着性をＡ、Ｂ、Ｃの３ランクで示した。なお、評価「Ａ」は「良」を、評価「Ｂ」は「やや良」を、評価「Ｃ」は「不良」をそれぞれ意味している。 FIG. 7 shows the relationship between the various production conditions in Examples 16 to 21 and Comparative Examples 7 to 9 and the respective evaluation results.
Here, in FIG. 7, as manufacturing conditions, a sputtering target material (bonding layer metal) in the bonding layer forming step, whether oxygen is introduced into the atmosphere in sputtering, and whether nitrogen is introduced into the atmosphere in sputtering are shown. It is described.
Further, in FIG. 7, as evaluation items, ohmic characteristics between the n contact layer 140a and the second bonding pad electrode 230 and adhesion between the n contact layer 140a and the second bonding pad electrode 230 are shown as A, B, Shown in rank C. The evaluation “A” means “good”, the evaluation “B” means “slightly good”, and the evaluation “C” means “bad”.
　実施例１６、１９および比較例７では、第２の接合層２２０を形成するためのスパッタのターゲット材としてＴａターゲットを用いた。また、実施例１７、２０および比較例８では、第２の接合層２２０を形成するためのスパッタのターゲット材としてＮｂターゲットを用いた。さらに、実施例１８、２１および比較例９では、第２の接合層２２０を形成するためのスパッタのターゲット材としてＴｉターゲットを用いた。
　また、実施例１６～１８ではスパッタの雰囲気中に酸素を導入し、実施例１９～２１ではスパッタの雰囲気中に窒素を導入した。これに対し、比較例７～９ではスパッタの雰囲気中に酸素や窒素を導入せず、Ａｒのみを用いた。
　さらに、実施例１６～２１および比較例７～９において、第２のバリア層２３０ａをＰｔで、第２のボンディング層２３０ｂをＡｕで、それぞれ作製した。 In Examples 16 and 19 and Comparative Example 7, a Ta target was used as a sputtering target material for forming the second bonding layer 220. In Examples 17 and 20 and Comparative Example 8, an Nb target was used as a sputtering target material for forming the second bonding layer 220. Further, in Examples 18 and 21 and Comparative Example 9, a Ti target was used as a sputtering target material for forming the second bonding layer 220.
In Examples 16 to 18, oxygen was introduced into the sputtering atmosphere, and in Examples 19 to 21, nitrogen was introduced into the sputtering atmosphere. On the other hand, in Comparative Examples 7 to 9, oxygen and nitrogen were not introduced into the sputtering atmosphere, and only Ar was used.
Further, in Examples 16 to 21 and Comparative Examples 7 to 9, the second barrier layer 230a was made of Pt, and the second bonding layer 230b was made of Au.
　次に、評価結果について説明する。
　実施例１６～２１においては、いずれも密着性の評価がＢ以上となった。すなわち、接合層形成工程においてスパッタの雰囲気に酸素あるいは窒素を導入することによって、ｎコンタクト層１４０ａと第２のボンディングパッド電極２３０との密着性が向上することが確認された。特に、酸素雰囲気下でＮｂあるいは窒素雰囲気下でＴａをターゲットとしてスパッタを行った実施例１７、１９では、密着性の評価がＡであることに加え、オーミック特性の評価もＡとなった。 Next, the evaluation result will be described.
In each of Examples 16 to 21, the adhesion evaluation was B or more. That is, it was confirmed that the adhesion between the n contact layer 140a and the second bonding pad electrode 230 is improved by introducing oxygen or nitrogen into the sputtering atmosphere in the bonding layer forming step. In particular, in Examples 17 and 19 where sputtering was performed using Nb or Ta as a target in an oxygen atmosphere, the adhesion evaluation was A, and the ohmic characteristic evaluation was A.
　一方、比較例７～９においては、オーミック特性の評価はすべてＡであるものの、密着性の評価がいずれもＣとなった。すなわち、接合層形成工程においてスパッタの雰囲気に酸素または窒素を導入しない場合には、ｎコンタクト層１４０ａと第２のボンディングパッド電極２３０との密着性が低下することが確認された。 On the other hand, in Comparative Examples 7 to 9, the evaluation of ohmic characteristics was all A, but the evaluation of adhesion was C. That is, it was confirmed that the adhesion between the n-contact layer 140a and the second bonding pad electrode 230 is reduced when oxygen or nitrogen is not introduced into the sputtering atmosphere in the bonding layer forming step.
　このように、バルブメタルの酸化物あるいは窒化物によって第２の接合層２２０を構成することにより、半導体発光素子１のｎコンタクト層１４０ａと第２の電極２４０との密着性が向上することが理解される。 As described above, it is understood that the adhesiveness between the n-contact layer 140a and the second electrode 240 of the semiconductor light emitting device 1 is improved by forming the second bonding layer 220 from the valve metal oxide or nitride. Is done.
　なお、本実施の形態が適用される半導体発光素子１では、バルブメタルの酸化物あるいは窒化物によって第２の接合層２２０が構成されているが、この第２の接合層２２０は電極として使用するのに十分な電気伝導特性を有している。これは、第２の接合層２２０において、バルブメタルの酸化物が、例えばＴａの場合においてはＴａ2Ｏ5の形ではなく、Ｔａ2Ｏ5-xの導電体の形で存在していること、あるいは、バルブメタルの窒化物が、例えばＴａの場合においてはＴａＮ1-xの導電型の形で存在していることに起因するものと考えられる。 In the semiconductor light emitting device 1 to which the present exemplary embodiment is applied, the second bonding layer 220 is made of valve metal oxide or nitride, and the second bonding layer 220 is used as an electrode. It has sufficient electric conduction characteristics. This is because, in the second bonding layer 220, the oxide of the valve metal exists not in the form of Ta 2 O 5 in the case of Ta, but in the form of a conductor of Ta 2 O 5-x . Alternatively, it is considered that the nitride of the valve metal exists due to the presence of TaN 1-x conductivity type in the case of Ta, for example.
＜第３の実施例＞
　本発明者は、各種製造条件を組み合わせて図１に示す半導体発光素子１の製造を行い、第１の電極２１０における透明電極１７０と第１のボンディングパッド電極２００との密着性について、公知のテープ剥離試験（テープ試験）に基づき検討を行った。なお、透明電極１７０と第１のボンディングパッド電極２００との密着性には、透明電極１７０と第１の接合層１９０との密着性および第１の接合層１９０と第１のボンディングパッド電極２００における第１のバリア層２００ａとの密着性が大きく影響している。 <Third embodiment>
The inventor manufactures the semiconductor light emitting device 1 shown in FIG. 1 by combining various manufacturing conditions, and the adhesiveness between the transparent electrode 170 and the first bonding pad electrode 200 in the first electrode 210 is a known tape. The examination was performed based on a peel test (tape test). The adhesion between the transparent electrode 170 and the first bonding pad electrode 200 includes the adhesion between the transparent electrode 170 and the first bonding layer 190 and the adhesion between the first bonding layer 190 and the first bonding pad electrode 200. Adhesion with the first barrier layer 200a has a great influence.
　図８～図１０は、実施例２２～４４および比較例１０～１５における各種製造条件と、密着性に関する評価結果との関係を示している。
　ここで、図８～図１０には、製造条件として、接合層形成工程におけるスパッタのターゲット材と、スパッタ雰囲気において窒素がアルゴン中に占める割合すなわちＮ2濃度（体積％）と、得られた第１の接合層１９０の厚さ（Å）とを記載している。
　また、図８～図１０には、評価項目として、第１の電極２１０における透明電極１７０と第１のボンディングパッド電極２００との密着性をＡ～Ｃの３ランクで示した。なお、評価「Ａ」は「良」、評価「Ｂ」は「やや良」、そして評価「Ｃ」は「不良」をそれぞれ意味している。 8 to 10 show the relationship between various manufacturing conditions in Examples 22 to 44 and Comparative Examples 10 to 15 and evaluation results on adhesion.
Here, FIGS. 8 to 10 show the manufacturing conditions as the sputtering target material in the bonding layer forming step, the ratio of nitrogen in argon in the sputtering atmosphere, that is, the N 2 concentration (volume%) obtained. The thickness (Å) of one bonding layer 190 is described.
8 to 10 show, as evaluation items, the adhesion between the transparent electrode 170 and the first bonding pad electrode 200 in the first electrode 210 in three ranks A to C. The evaluation “A” means “good”, the evaluation “B” means “slightly good”, and the evaluation “C” means “bad”.
　なお、図８は、ターゲット材としてＴａを用いた場合における実施例（実施例２２～３２）および比較例（比較例１０、１１）を示している。また、図９は、ターゲット材としてＷを用いた場合における実施例（実施例３３～３８）および比較例（比較例１２、１３）を示している。さらに、図１０は、ターゲット材としてＴｉを用いた場合における実施例（実施例３９～４４）および比較例（比較例１４、１５）を示している。これら実施例２２～４４および比較例１０～１５においては、透明電極１７０としてＩＺＯ膜を用い、第１のバリア層２００ａをＰｔで１０００オングストローム、第１のボンディング層２００ｂをＡｕで５０００オングストロームとし、それぞれ作製した。　 FIG. 8 shows examples (Examples 22 to 32) and comparative examples (Comparative Examples 10 and 11) when Ta is used as a target material. FIG. 9 shows Examples (Examples 33 to 38) and Comparative Examples (Comparative Examples 12 and 13) when W is used as a target material. Further, FIG. 10 shows Examples (Examples 39 to 44) and Comparative Examples (Comparative Examples 14 and 15) when Ti is used as a target material. In these Examples 22 to 44 and Comparative Examples 10 to 15, an IZO film was used as the transparent electrode 170, the first barrier layer 200a was 1000 angstroms in Pt, and the first bonding layer 200b was 5000 angstroms in Au. Produced. *
　次に、評価結果について説明する。
　図８に示すように、ターゲット材としてＴａを用いた場合、実施例２２～３２において密着性の評価がＡまたはＢとなった。そして、第１の接合層１９０の厚さを１００オングストロームで一定とした実施例２２、２３、２５、３０～３２では、スパッタ雰囲気中のＮ2濃度を２０体積％以上とすることにより、密着性の評価がＡとなることがわかった。これに対し、スパッタ雰囲気中のＮ2濃度を０体積％または１．０体積％とした比較例１０、１１では、いずれも密着性の評価がＣとなった。
　また、スパッタ雰囲気中のＮ2濃度を７．５体積％で一定とした実施例２４～２９では、第１の接合層１９０の厚さを２５０オングストローム以上とすることにより、密着性の評価がＡとなった。
　なお、本発明者は、ターゲット材としてＴａを用いた場合において、スパッタ雰囲気中のＮ2濃度を５０体積％超とした条件下でスパッタによる第１の接合層１９０の成膜を試行したが、成膜レートが低下し、生産上実用的ではなかった。 Next, the evaluation result will be described.
As shown in FIG. 8, when Ta was used as the target material, the adhesion evaluation in Examples 22 to 32 was A or B. In Examples 22, 23, 25, and 30 to 32 in which the thickness of the first bonding layer 190 is constant at 100 angstroms, the N 2 concentration in the sputtering atmosphere is set to 20% by volume or more, thereby improving the adhesion. Was found to be A. On the other hand, in Comparative Examples 10 and 11 in which the N 2 concentration in the sputtering atmosphere was 0% by volume or 1.0% by volume, the adhesion evaluation was C.
Further, in Examples 24 to 29 in which the N 2 concentration in the sputtering atmosphere was constant at 7.5% by volume, the adhesiveness was evaluated as A by setting the thickness of the first bonding layer 190 to 250 angstroms or more. It became.
The inventor tried to form the first bonding layer 190 by sputtering under the condition that the N 2 concentration in the sputtering atmosphere was more than 50% by volume when Ta was used as the target material. The film formation rate decreased, and it was not practical in production.
　図９に示すように、ターゲット材としてＷを用いた場合、実施例３３～３８において密着性の評価がＡまたはＢとなった。そして、第１の接合層１９０の厚さを１００オングストロームで一定とした実施例３３～３８では、スパッタ雰囲気中のＮ2濃度を１０体積％以上とすることにより、密着性の評価がＡとなることがわかった。これに対し、スパッタ雰囲気中のＮ2濃度を０体積％または１．０体積％とした比較例１２、１３では、いずれも密着性の評価がＣとなった。
　なお、本発明者は、ターゲット材としてＷを用いた場合において、スパッタ雰囲気中のＮ2濃度を５０体積％超とした条件下でスパッタによる第１の接合層１９０の成膜を試行したが、成膜レートが低下し、生産上実用的ではなかった。 As shown in FIG. 9, when W was used as the target material, the adhesion evaluation in Examples 33 to 38 was A or B. In Examples 33 to 38 in which the thickness of the first bonding layer 190 is constant at 100 Å, the adhesion evaluation is A by setting the N 2 concentration in the sputtering atmosphere to 10 vol% or more. I understood it. On the other hand, in Comparative Examples 12 and 13 in which the N 2 concentration in the sputtering atmosphere was 0% by volume or 1.0% by volume, the evaluation of adhesion was C.
The inventor tried to form the first bonding layer 190 by sputtering under the condition that the N 2 concentration in the sputtering atmosphere was more than 50% by volume when W was used as the target material. The film formation rate decreased, and it was not practical in production.
　図１０に示すように、ターゲット材としてＴｉを用いた場合、実施例３９～４４において密着性の評価がＡまたはＢとなった。そして、第１の接合層１９０の厚さを１００オングストロームで一定とした実施例３９～４４では、スパッタ雰囲気中のＮ2濃度を１０体積％以上とすることにより、密着性の評価がＡとなることがわかった。これに対し、スパッタ雰囲気中のＮ2濃度を０体積％または１．０体積％とした比較例１４、１５では、いずれも密着性の評価がＣとなった。
　なお、本発明者は、ターゲット材としてＴｉを用いた場合において、スパッタ雰囲気中のＮ2濃度を５０体積％超とした条件下でスパッタによる第１の接合層１９０の成膜を試行したが、成膜レートが低下し、生産上実用的ではなかった。 As shown in FIG. 10, when Ti was used as the target material, the adhesion evaluation in Examples 39 to 44 was A or B. In Examples 39 to 44 in which the thickness of the first bonding layer 190 is constant at 100 angstroms, the adhesion evaluation is A by setting the N 2 concentration in the sputtering atmosphere to 10% by volume or more. I understood it. On the other hand, in Comparative Examples 14 and 15 in which the N 2 concentration in the sputtering atmosphere was 0% by volume or 1.0% by volume, the adhesion evaluation was C.
Note that the present inventor tried to form the first bonding layer 190 by sputtering under the condition that the N 2 concentration in the sputtering atmosphere was more than 50% by volume when Ti was used as the target material. The film formation rate decreased, and it was not practical in production.
　図１１は、Ｔａをターゲット材とし、且つ、厚さを一定とし、スパッタ雰囲気中のＮ2濃度をそれぞれ異ならせて第１の接合層１９０を形成した場合におけるテープ剥離試験の結果の一例を説明するための図である。なお、ここでは、１枚のウエハ状の基板１１０のほぼ全面に、中間層１２０、下地層１３０、ｎ型半導体層１４０、発光層１５０、ｐ型半導体層１６０、透明電極１７０、第１の接合層１９０および第１のボンディングパッド電極２００（第１のバリア層２００ａおよび第１のボンディング層２００ｂ）の形成を行ったものを、テープ剥離試験の対象として用いている。そして、第１の接合層１９０の厚さは１００オングストロームとし、Ｐｔからなる第１のバリア層２００ａの厚さは１０００オングストロームとし、Ａｕからなる第１のボンディング層２００ｂの厚さは５０００オングストロームとした。 FIG. 11 illustrates an example of a result of the tape peeling test in the case where the first bonding layer 190 is formed by using Ta as a target material, having a constant thickness, and varying the N 2 concentration in the sputtering atmosphere. It is a figure for doing. Note that, here, the intermediate layer 120, the base layer 130, the n-type semiconductor layer 140, the light-emitting layer 150, the p-type semiconductor layer 160, the transparent electrode 170, and the first junction are formed on almost the entire surface of one wafer-like substrate 110. The layer 190 and the first bonding pad electrode 200 (the first barrier layer 200a and the first bonding layer 200b) formed thereon are used as targets for the tape peeling test. The thickness of the first bonding layer 190 is 100 angstroms, the thickness of the first barrier layer 200a made of Pt is 1000 angstroms, and the thickness of the first bonding layer 200b made of Au is 5000 angstroms. .
　ここで、図１１（ａ）はスパッタ雰囲気中のＮ2濃度を０体積％とした場合（比較例１０）の結果を、図１１（ｂ）はスパッタ雰囲気中のＮ2濃度を１０体積％とした場合（実施例３０）の結果を、図１１（ｃ）はスパッタ雰囲気中のＮ2濃度を１５体積％とした場合（実施例、比較例に記載せず）の結果を、図１１（ｄ）はスパッタ雰囲気中のＮ2濃度を２０体積％とした場合（実施例３１）の結果を、図１１（ｅ）はスパッタ雰囲気中のＮ2濃度を２５体積％とした場合（実施例、比較例に記載せず）の結果を、図１１（ｆ）はスパッタ雰囲気中のＮ2濃度を３０体積％とした場合（実施例、比較例に記載せず）の結果を、それぞれ示している。 Here, FIG. 11A shows the result when the N 2 concentration in the sputtering atmosphere is 0% by volume (Comparative Example 10), and FIG. 11B shows the N 2 concentration in the sputtering atmosphere is 10% by volume. FIG. 11 (c) shows the results when the N 2 concentration in the sputtering atmosphere is 15% by volume (not shown in the examples and comparative examples). ) Shows the result when the N 2 concentration in the sputtering atmosphere is 20% by volume (Example 31), and FIG. 11E shows the result when the N 2 concentration in the sputtering atmosphere is 25% by volume (Example, comparison). FIG. 11 (f) shows the results when the N 2 concentration in the sputtering atmosphere is 30% by volume (not shown in the examples and comparative examples).
　図１１（ａ）～（ｆ）より、スパッタ雰囲気中のＮ2濃度を高めていくことにより、膜の剥がれが生じにくくなっていくことが理解される。特に、スパッタ雰囲気中のＮ2濃度を１５体積％以上、より好ましくは２０体積％以上とすることにより、第１の接合層１９０を介した透明電極１７０および第１のボンディングパッド電極２００との密着性が高まり、膜の剥がれがほとんど生じなくなることが理解される。 From FIGS. 11 (a) to 11 (f), it is understood that peeling of the film is less likely to occur by increasing the N 2 concentration in the sputtering atmosphere. In particular, the N 2 concentration in the sputtering atmosphere is set to 15% by volume or more, more preferably 20% by volume or more, so that the transparent electrode 170 and the first bonding pad electrode 200 are in close contact with each other through the first bonding layer 190. It is understood that the film is improved and the film is hardly peeled off.
　一方、図１２は、Ｔａをターゲット材とし、且つ、スパッタ雰囲気中のＮ2濃度を７．５体積％で一定とし（後述する図１２（ａ）を除く）、厚さをそれぞれ異ならせて第１の接合層１９０を形成した場合におけるテープ剥離試験の結果の一例を説明するための図である。なお、ここでは、上述した場合と同様、１枚のウエハ状の基板１１０のほぼ全面に、中間層１２０、下地層１３０、ｎ型半導体層１４０、発光層１５０、ｐ型半導体層１６０、透明電極１７０、第１の接合層１９０および第１のボンディングパッド電極２００（第１のバリア層２００ａおよび第１のボンディング層２００ｂ）の形成を行ったものを、テープ剥離試験の対象として用いている。そして、第１の接合層１９０の厚さは２０～１０００オングストロームとし、Ｐｔからなる第１のバリア層２００ａの厚さは１０００オングストロームとし、Ａｕからなる第１のボンディング層２００ｂの厚さは５０００オングストロームとした。 On the other hand, in FIG. 12, Ta is used as the target material, and the N 2 concentration in the sputtering atmosphere is kept constant at 7.5% by volume (except for FIG. 12A described later), and the thickness is varied. It is a figure for demonstrating an example of the result of a tape peeling test in case the 1 joining layer 190 is formed. Here, as in the case described above, the intermediate layer 120, the base layer 130, the n-type semiconductor layer 140, the light emitting layer 150, the p-type semiconductor layer 160, and the transparent electrode are formed on almost the entire surface of one wafer-like substrate 110. 170, the first bonding layer 190, and the first bonding pad electrode 200 (the first barrier layer 200a and the first bonding layer 200b) are used as the targets of the tape peeling test. The thickness of the first bonding layer 190 is 20 to 1000 angstroms, the thickness of the first barrier layer 200a made of Pt is 1000 angstroms, and the thickness of the first bonding layer 200b made of Au is 5000 angstroms. It was.
　ここで、図１２（ａ）は、スパッタ雰囲気中のＮ2濃度を０体積％とすることで、第１の接合層１９０を窒化していないＴａで形成すると共にその厚さを２０オングストロームとした場合（実施例、比較例に記載せず）の結果を、図１２（ｂ）は第１の接合層１９０を窒素雰囲気下で形成すると共にその厚さを２０オングストロームとした場合（実施例２４）の結果を、図１２（ｃ）は第１の接合層１９０を窒素雰囲気下で形成すると共にその厚さを１００オングストロームとした場合（実施例２５）の結果を、図１２（ｄ）は第１の接合層１９０を窒素雰囲気下で形成すると共にその厚さを２５０オングストロームとした場合（実施例２６）の結果を、図１２（ｅ）は第１の接合層１９０を窒素雰囲気下で形成すると共にその厚さを４００オングストロームとした場合（実施例２７）の結果を、図１２（ｆ）は第１の接合層１９０を窒素雰囲気下で形成すると共にその厚さを７００オングストロームとした場合（実施例２８）の結果を、図１２（ｇ）は第１の接合層１９０を窒素雰囲気下で形成すると共にその厚さを１０００オングストロームとした場合（実施例２９）の結果を、それぞれ示している。 Here, in FIG. 12A, the N 2 concentration in the sputtering atmosphere is set to 0% by volume, so that the first bonding layer 190 is formed of Ta which is not nitrided, and the thickness thereof is 20 Å. FIG. 12B shows the result of the case (not described in Examples and Comparative Examples). FIG. 12B shows the case where the first bonding layer 190 is formed in a nitrogen atmosphere and its thickness is 20 angstroms (Example 24). FIG. 12C shows the results when the first bonding layer 190 is formed in a nitrogen atmosphere and the thickness thereof is 100 angstroms (Example 25), and FIG. When the first bonding layer 190 is formed under a nitrogen atmosphere and the thickness thereof is 250 angstroms (Example 26), FIG. 12E shows the first bonding layer 190 formed under a nitrogen atmosphere. Its thickness is 400 FIG. 12 (f) shows the results when the first bonding layer 190 is formed in a nitrogen atmosphere and the thickness is 700 Å (Example 28). FIG. 12G shows the results when the first bonding layer 190 is formed in a nitrogen atmosphere and the thickness thereof is 1000 angstroms (Example 29).
　図１２（ａ）～（ｇ）より、スパッタ雰囲気中にＮ2を導入することにより、スパッタ雰囲気中にＮ2を導入しない場合と比較して、膜の剥がれが生じにくくなっていくことが理解される。また、図１２（ｂ）～（ｇ）より、窒素雰囲気中でのスパッタで形成される第１の接合層１９０の厚さを増加させることにより、膜の剥がれが生じにくくなっていくことが理解される。特に第１の接合層１９０の厚さを１００オングストローム以上、より好ましくは２５０オングストローム以上とすることにより、第１の接合層１９０を介した透明電極１７０および第１のボンディングパッド電極２００との密着性が高まり、膜の剥がれがほとんど生じなくなることが理解される。 12 (a) to 12 (g), it is understood that when N 2 is introduced into the sputtering atmosphere, film peeling is less likely to occur than when N 2 is not introduced into the sputtering atmosphere. Is done. Further, from FIGS. 12B to 12G, it is understood that the film is less likely to be peeled off by increasing the thickness of the first bonding layer 190 formed by sputtering in a nitrogen atmosphere. Is done. In particular, by setting the thickness of the first bonding layer 190 to 100 angstroms or more, more preferably 250 angstroms or more, adhesion between the transparent electrode 170 and the first bonding pad electrode 200 via the first bonding layer 190 is achieved. It is understood that peeling of the film hardly occurs.
　図１３は、実施例２３（ターゲット材：Ｔａ、スパッタ雰囲気中のＮ2濃度：５．０体積％）に対応する半導体発光素子１における第１の電極２１０を、Ｘ線光電子分光法（ＸＰＳ：X-ray Photoelectron Spectroscopy）の深さ分析によって解析した結果を示している。ただし、ここでは、透明電極１７０上に第１の接合層１９０を積層し、第１の接合層１９０上に第１のバリア層２００ａを積層したものを解析用の試料とした。また、この例では、第１の接合層１９０の厚さを、１００オングストロームではなく４００オングストロームとした。
　図１３において、横軸はＡｒガスを用いたスパッタリング時間であり、縦軸は各元素の原子濃度である。なお、スパッタリング時間は、第１の電極２１０の深さ方向の位置に対応している。 FIG. 13 shows X-ray photoelectron spectroscopy (XPS) of the first electrode 210 in the semiconductor light emitting device 1 corresponding to Example 23 (target material: Ta, N 2 concentration in sputtering atmosphere: 5.0% by volume). X-ray Photoelectron Spectroscopy) shows the result of analysis by depth analysis. However, here, a sample for analysis was obtained by laminating the first bonding layer 190 on the transparent electrode 170 and laminating the first barrier layer 200a on the first bonding layer 190. In this example, the thickness of the first bonding layer 190 is set to 400 Å instead of 100 Å.
In FIG. 13, the horizontal axis represents the sputtering time using Ar gas, and the vertical axis represents the atomic concentration of each element. Note that the sputtering time corresponds to the position of the first electrode 210 in the depth direction.
　図１３から、スパッタリング時間が０～２００ｓｅｃの領域すなわち積層された透明電極１７０、第１の接合層１９０および第１のバリア層２００ａの最上部側においては、膜中に第１のバリア層２００ａを構成するＰｔが多く存在していることがわかる。
　また、スパッタリング時間が２００～６００ｓｅｃの領域では、第１の接合層１９０を構成するＴａおよびＮが多く存在していること、すなわち、Ｔａの一部が窒化した状態で存在していることがわかる。なお、この解析結果において、第１の接合層１９０における窒素元素の濃度は、最大で５％弱となるレベルとなっている。
　次に、スパッタリング時間が６００～１５００ｓｅｃの領域では、ＩｎとＺｎとＯとが存在し、ＩｎよりもＺｎの濃度が低いこと、すなわち、ＩＺＯの状態で存在していることがわかる。 From FIG. 13, in the region where the sputtering time is 0 to 200 sec, that is, on the uppermost side of the laminated transparent electrode 170, the first bonding layer 190, and the first barrier layer 200a, the first barrier layer 200a is formed in the film. It can be seen that a large amount of Pt exists.
In addition, in the region where the sputtering time is 200 to 600 seconds, it can be seen that a large amount of Ta and N constituting the first bonding layer 190 exist, that is, a part of Ta exists in a nitrided state. . In this analysis result, the concentration of the nitrogen element in the first bonding layer 190 is at a level that is a little less than 5% at the maximum.
Next, it can be seen that In, Zn, and O exist in the region where the sputtering time is 600 to 1500 seconds, and that the Zn concentration is lower than In, that is, exists in an IZO state.
　また、図１４は、実施例３０（ターゲット材：Ｔａ、スパッタ雰囲気中のＮ2濃度：１０体積％）に対応する半導体発光素子１における第１の電極２１０を、ＸＰＳの深さ分析によって解析した結果を示している。ただし、上述したものと同様、透明電極１７０上に第１の接合層１９０を積層し、第１の接合層１９０上に第１のバリア層２００ａを積層したものを解析用の試料とした。また、この例では、第１の接合層１９０の厚さを、１００オングストロームではなく４００オングストロームとした。
　なお、図１４における横軸および縦軸は、図１３で説明したものと同じである。 FIG. 14 shows the XPS depth analysis of the first electrode 210 in the semiconductor light emitting device 1 corresponding to Example 30 (target material: Ta, N 2 concentration in sputtering atmosphere: 10% by volume). Results are shown. However, as described above, a sample for analysis was obtained by laminating the first bonding layer 190 on the transparent electrode 170 and laminating the first barrier layer 200a on the first bonding layer 190. In this example, the thickness of the first bonding layer 190 is set to 400 Å instead of 100 Å.
Note that the horizontal and vertical axes in FIG. 14 are the same as those described in FIG.
　図１４から、スパッタリング時間が０～２００ｓｅｃの領域すなわち積層された透明電極１７０、第１の接合層１９０および第１のバリア層２００ａの最上部側においては、膜中に第１のバリア層２００ａを構成するＰｔが多く存在していることがわかる。
　また、スパッタリング時間が２００～６００ｓｅｃの領域では、第１の接合層１９０を構成するＴａおよびＮが多く存在していること、すなわち、Ｔａの一部が窒化した状態で存在していることがわかる。なお、この解析結果において、第１の接合層１９０における窒素元素の濃度は、最大で５％を超えるレベルとなっている。
　次に、スパッタリング時間が６００～１５００ｓｅｃの領域では、ＩｎとＺｎとＯとが存在し、ＩｎよりもＺｎの濃度が低いこと、すなわち、ＩＺＯの状態で存在していることがわかる。 From FIG. 14, in the region where the sputtering time is 0 to 200 seconds, that is, on the uppermost side of the laminated transparent electrode 170, first bonding layer 190, and first barrier layer 200a, the first barrier layer 200a is formed in the film. It can be seen that a large amount of Pt exists.
In addition, in the region where the sputtering time is 200 to 600 seconds, it can be seen that a large amount of Ta and N constituting the first bonding layer 190 exist, that is, a part of Ta exists in a nitrided state. . In this analysis result, the concentration of the nitrogen element in the first bonding layer 190 is at a level exceeding 5% at the maximum.
Next, it can be seen that In, Zn, and O exist in the region where the sputtering time is 600 to 1500 seconds, and that the Zn concentration is lower than In, that is, exists in an IZO state.
　さらに、図１５は、実施例３２（ターゲット材：Ｔａ、スパッタ雰囲気中のＮ2濃度：５０体積％）に対応する半導体発光素子１における第１の電極２１０を、ＸＰＳの深さ分析によって解析した結果を示している。ただし、上述したものと同様、透明電極１７０上に第１の接合層１９０を積層し、第１の接合層１９０上に第１のバリア層２００ａを積層したものを解析用の試料とした。また、この例では、第１の接合層１９０の厚さを、１００オングストロームではなく４００オングストロームとした。
　なお、図１５における横軸および縦軸は、図１３で説明したものと同じである。 Further, FIG. 15 shows the XPS depth analysis of the first electrode 210 in the semiconductor light emitting device 1 corresponding to Example 32 (target material: Ta, N 2 concentration in sputtering atmosphere: 50% by volume). Results are shown. However, as described above, a sample for analysis was obtained by laminating the first bonding layer 190 on the transparent electrode 170 and laminating the first barrier layer 200a on the first bonding layer 190. In this example, the thickness of the first bonding layer 190 is set to 400 Å instead of 100 Å.
Note that the horizontal and vertical axes in FIG. 15 are the same as those described in FIG.
　図１５から、スパッタリング時間が０～２００ｓｅｃの領域すなわち積層された透明電極１７０、第１の接合層１９０および第１のバリア層２００ａの最上部側においては、膜中に第１のバリア層２００ａを構成するＰｔが多く存在していることがわかる。
　また、スパッタリング時間が２００～６００ｓｅｃの領域では、第１の接合層１９０を構成するＴａおよびＮが多く存在していること、すなわち、Ｔａの一部が窒化した状態で存在していることがわかる。なお、この解析結果において、第１の接合層１９０における窒素元素の濃度は、最大で１５％を超えるレベルとなっている。
　次に、スパッタリング時間が６００～１５００ｓｅｃの領域では、ＩｎとＺｎとＯとが存在し、ＩｎよりもＺｎの濃度が低いこと、すなわち、ＩＺＯの状態で存在していることがわかる。 From FIG. 15, in the region where the sputtering time is 0 to 200 seconds, that is, on the uppermost side of the laminated transparent electrode 170, the first bonding layer 190, and the first barrier layer 200a, the first barrier layer 200a is formed in the film. It can be seen that a large amount of Pt exists.
In addition, in the region where the sputtering time is 200 to 600 seconds, it can be seen that a large amount of Ta and N constituting the first bonding layer 190 exist, that is, a part of Ta exists in a nitrided state. . In this analysis result, the concentration of the nitrogen element in the first bonding layer 190 is at a level exceeding 15% at the maximum.
Next, it can be seen that In, Zn, and O exist in the region where the sputtering time is 600 to 1500 seconds, and that the Zn concentration is lower than In, that is, exists in an IZO state.
　一方、図１６は、比較例１０（ターゲット材：Ｔａ、スパッタ雰囲気中のＮ2濃度：０体積％）に対応する半導体発光素子１における第１の電極２１０を、ＸＰＳの深さ分析によって解析した結果を示している。ただし、上述したものと同様、透明電極１７０上に第１の接合層１９０を積層し、第１の接合層１９０上に第１のバリア層２００ａを積層したものを解析用の試料とした。また、この例では、第１の接合層１９０の厚さを、１００オングストロームではなく４００オングストロームとした。
　なお、図１０における横軸および縦軸は、図１３で説明したものと同じである。 On the other hand, FIG. 16 analyzed the first electrode 210 in the semiconductor light emitting device 1 corresponding to Comparative Example 10 (target material: Ta, N 2 concentration in sputtering atmosphere: 0% by volume) by XPS depth analysis. Results are shown. However, as described above, a sample for analysis was obtained by laminating the first bonding layer 190 on the transparent electrode 170 and laminating the first barrier layer 200a on the first bonding layer 190. In this example, the thickness of the first bonding layer 190 is set to 400 Å instead of 100 Å.
Note that the horizontal and vertical axes in FIG. 10 are the same as those described in FIG.
　図１６から、スパッタリング時間が０～２００ｓｅｃの領域すなわち積層された透明電極１７０、第１の接合層１９０および第１のバリア層２００ａの最上部側においては、膜中に第１のバリア層２００ａを構成するＰｔが多く存在していることがわかる。
　また、スパッタリング時間が２００～６００ｓｅｃの領域では、第１の接合層１９０を構成するＴａが多く存在していること、すなわち、Ｔａが窒化していない状態で存在していることがわかる。
　次に、スパッタリング時間が６００～１５００ｓｅｃの領域では、ＩｎとＺｎとＯとが存在し、ＩｎよりもＺｎの濃度が低いこと、すなわち、ＩＺＯの状態で存在していることがわかる。 From FIG. 16, in the region where the sputtering time is 0 to 200 sec, that is, on the uppermost side of the laminated transparent electrode 170, the first bonding layer 190, and the first barrier layer 200a, the first barrier layer 200a is formed in the film. It can be seen that a large amount of Pt exists.
Further, it can be seen that in the region where the sputtering time is 200 to 600 seconds, a large amount of Ta constituting the first bonding layer 190 exists, that is, Ta exists in a state where it is not nitrided.
Next, it can be seen that In, Zn, and O exist in the region where the sputtering time is 600 to 1500 seconds, and that the Zn concentration is lower than In, that is, exists in an IZO state.
　したがって、図１３～図１６より明らかなように、本実施の形態で説明した手法、より具体的には窒素雰囲気中でスパッタを行うことで第１の接合層１９０を形成することにより、バルブメタル（ここではＴａ）の窒化物が製膜され得ることが理解される。
　また、図１３～図１６より、第１の接合層１９０を形成する際のスパッタ雰囲気中のＮ2濃度を高めるほど、ＴａおよびＮのピーク形状がシャープになること、すなわち、Ｔａが透明電極１７０側に拡散されにくくなっていることが理解される。多数のＴａが透明電極１７０側に拡散した場合、侵入したＴａが透明電極１７０を構成するＩＺＯを分解してＩｎを析出させるおそれがある。このようにして、透明電極１７０からＩｎが析出すると、透明電極１７０と第１の接合層１９０との密着性が低下し、結果として第１のボンディングパッド電極２００の剥がれが生じやすくなる。
　したがって、第１の接合層１９０としてバルブメタルの窒化物を含める構成を採用することで、第１の接合層１９０を介した透明電極１７０と第１のボンディングパッド電極２００との密着性が高まり、剥がれが生じにくくなることが理解される。 Therefore, as apparent from FIGS. 13 to 16, the valve metal is formed by forming the first bonding layer 190 by the method described in this embodiment, more specifically, by performing sputtering in a nitrogen atmosphere. It is understood that a nitride of (here Ta) can be deposited.
13 to 16, the higher the N 2 concentration in the sputtering atmosphere when forming the first bonding layer 190, the sharper the peak shapes of Ta and N, that is, Ta becomes the transparent electrode 170. It is understood that it is difficult to diffuse to the side. When a large number of Ta diffuses to the transparent electrode 170 side, there is a possibility that the invaded Ta decomposes IZO constituting the transparent electrode 170 and precipitates In. Thus, when In is deposited from the transparent electrode 170, the adhesion between the transparent electrode 170 and the first bonding layer 190 is lowered, and as a result, the first bonding pad electrode 200 is easily peeled off.
Therefore, by adopting a configuration including a valve metal nitride as the first bonding layer 190, the adhesion between the transparent electrode 170 and the first bonding pad electrode 200 via the first bonding layer 190 is increased. It will be understood that peeling is less likely to occur.
　なお、本実施の形態が適用される半導体発光素子１では、バルブメタルの窒化物によって第１の接合層１９０が構成されているが、この第１の接合層１９０は電極として使用するのに十分な電気伝導特性を有している。これは、第１の接合層１９０において、バルブメタルの窒化物が、例えばＴａの場合においてはＴａＮの比抵抗値が比較的低いことに起因するもの、ＴａＮの形ではなくＴａＮ1-xの形で存在していることに起因するもの、あるいは、第１の接合層１９０がＴａとＴａＮとが混在した状態で形成されていることに起因するもの、と考えられる。 In the semiconductor light emitting device 1 to which the present exemplary embodiment is applied, the first bonding layer 190 is formed of a nitride of valve metal, but the first bonding layer 190 is sufficient for use as an electrode. It has excellent electrical conduction characteristics. This is because, in the first bonding layer 190, a nitride of valve metal, for example those in the case of Ta is due to the relatively low resistivity of TaN, form rather than in the form of TaN TaN 1-x It can be considered that the first bonding layer 190 is formed in a state where Ta and TaN are mixed.
１…半導体発光素子、１００…積層半導体層、１１０…基板、１２０…中間層、１３０…下地層、１４０…ｎ型半導体層、１４０ａ…ｎコンタクト層、１４０ｂ…ｎクラッド層、１４０ｃ…半導体層露出面、１５０…発光層、１５０ａ…障壁層、１５０ｂ…井戸層、１６０…ｐ型半導体層、１６０ａ…ｐクラッド層、１６０ｂ…ｐコンタクト層、１６０ｃ…上面、１７０…透明電極、１８０…保護層、１９０…第１の接合層、２００…第１のボンディングパッド電極、２００ａ…第１のバリア層、２００ｂ…第１のボンディング層、２１０…第１の電極、２２０…第２の接合層、２３０…第２のボンディングパッド電極、２３０ａ…第２のバリア層、２３０ｂ…第２のボンディング層、２４０…第２の電極 DESCRIPTION OF SYMBOLS 1 ... Semiconductor light-emitting device, 100 ... Laminated semiconductor layer, 110 ... Substrate, 120 ... Intermediate layer, 130 ... Underlayer, 140 ... N-type semiconductor layer, 140a ... n contact layer, 140b ... N clad layer, 140c ... Semiconductor layer exposure 150, light emitting layer, 150a, barrier layer, 150b, well layer, 160, p-type semiconductor layer, 160a, p-clad layer, 160b, p-contact layer, 160c, upper surface, 170, transparent electrode, 180, protective layer, DESCRIPTION OF SYMBOLS 190 ... 1st joining layer, 200 ... 1st bonding pad electrode, 200a ... 1st barrier layer, 200b ... 1st bonding layer, 210 ... 1st electrode, 220 ... 2nd joining layer, 230 ... Second bonding pad electrode, 230a ... second barrier layer, 230b ... second bonding layer, 240 ... second electrode

Claims (20)

  1. 　基板と、
    　発光層を含み前記基板上に積層される積層半導体層と、
    　インジウム酸化物を含み前記積層半導体層上に積層される透明電極と、
    　弁作用金属より選ばれた少なくとも一種の元素を含むとともに前記透明電極と接する側が当該元素の酸化物または窒化物の少なくともいずれか一方を含むように当該透明電極上に積層される接合層と、
    　前記接合層上に積層されて外部との電気的な接続に用いられる接続電極と
    を含む半導体発光素子。     A substrate,
    A laminated semiconductor layer including a light emitting layer and laminated on the substrate;
    A transparent electrode comprising indium oxide and laminated on the laminated semiconductor layer;
    A bonding layer that includes at least one element selected from valve metals and is laminated on the transparent electrode so that a side in contact with the transparent electrode includes at least one of an oxide or a nitride of the element;
    A semiconductor light emitting device including a connection electrode stacked on the bonding layer and used for electrical connection with the outside.
  2. 　前記接合層が、Ａｌ、Ｔｉ、Ｚｎ、Ｚｒ、Ｎｂ、Ｗ、Ｍｇ、Ｂｉ、Ｓｉ、Ｈｆ、Ｔａからなる群より選ばれた少なくとも一種の元素を含んでいることを特徴とする請求項１記載の半導体発光素子。 2. The bonding layer includes at least one element selected from the group consisting of Al, Ti, Zn, Zr, Nb, W, Mg, Bi, Si, Hf, and Ta. Semiconductor light emitting device.
  3. 　前記接合層が前記元素の窒化物を含む場合に、
    　前記接合層が、Ｔａ、Ｗ、Ｔｉからなる群より選ばれた少なくとも一種の元素を含んでいることを特徴とする請求項２記載の半導体発光素子。     When the bonding layer includes a nitride of the element,
    3. The semiconductor light emitting element according to claim 2, wherein the bonding layer contains at least one element selected from the group consisting of Ta, W, and Ti.
  4. 　前記接合層が前記元素の酸化物を含む場合に、
    　前記接合層が、Ｔａ、Ｎｂ、Ｔｉからなる群より選ばれた少なくとも一種の元素を含んでいることを特徴とする請求項２記載の半導体発光素子。     When the bonding layer contains an oxide of the element,
    3. The semiconductor light emitting element according to claim 2, wherein the bonding layer contains at least one element selected from the group consisting of Ta, Nb, and Ti.
  5. 　前記接続電極が、Ａｕ、Ａｌまたはこれらの金属のいずれかを含む合金からなるボンディング層を有していることを特徴とする請求項１記載の半導体発光素子。 2. The semiconductor light emitting element according to claim 1, wherein the connection electrode has a bonding layer made of Au, Al, or an alloy containing any of these metals.
  6. 　前記接続電極が、前記接合層と前記ボンディング層との間に積層されるバリア層をさらに備え、
    　前記バリア層が、Ａｇ、Ａｌ、Ｒｕ、Ｒｈ、Ｐｄ、Ｏｓ、Ｉｒ、Ｐｔ、Ｔｉ、Ｗ、Ｍｏ、Ｎｉ、Ｃｏ、Ｚｒ、Ｈｆ、Ｔａ、Ｎｂのうちの何れかまたはこれら金属の何れかを含む合金からなるものであることを特徴とする請求項５記載の半導体発光素子。     The connection electrode further comprises a barrier layer laminated between the bonding layer and the bonding layer;
    The barrier layer is made of one of Ag, Al, Ru, Rh, Pd, Os, Ir, Pt, Ti, W, Mo, Ni, Co, Zr, Hf, Ta, Nb, or any of these metals. 6. The semiconductor light emitting device according to claim 5, wherein the semiconductor light emitting device is made of an alloy containing the same.
  7. 　前記透明電極が、前記インジウム酸化物および亜鉛酸化物を含んで構成されることを特徴とする請求項１記載の半導体発光素子。 2. The semiconductor light emitting device according to claim 1, wherein the transparent electrode includes the indium oxide and zinc oxide.
  8. 　前記積層半導体層が、ＩＩＩ族窒化物半導体にて構成されていることを特徴とする請求項１項記載の半導体発光素子。 2. The semiconductor light emitting element according to claim 1, wherein the laminated semiconductor layer is made of a group III nitride semiconductor.
  9. 　基板と、
    　発光層を有するＩＩＩ族窒化物半導体にて構成され前記基板上に積層される積層半導体層と、
    　弁作用金属より選ばれた少なくとも一種の元素を含むとともに前記積層半導体層のうちの一つの半導体層と接する側が当該元素の酸化物または窒化物の少なくともいずれか一方を含むように当該一つの半導体層上に積層される接合層と、
    　前記接合層上に積層されて外部との電気的な接続に用いられる接続電極と
    を含む半導体発光素子。     A substrate,
    A laminated semiconductor layer composed of a group III nitride semiconductor having a light emitting layer and laminated on the substrate;
    One semiconductor layer including at least one element selected from valve metals and a side in contact with one semiconductor layer of the stacked semiconductor layers including at least one of an oxide or a nitride of the element A bonding layer laminated thereon;
    A semiconductor light emitting device including a connection electrode stacked on the bonding layer and used for electrical connection with the outside.
  10. 　前記接合層が、Ａｌ、Ｔｉ、Ｚｎ、Ｚｒ、Ｎｂ、Ｍｇ、Ｂｉ、Ｓｉ、Ｈｆ、Ｔａからなる群より選ばれた少なくとも一種の元素を含んでいることを特徴とする請求項９記載の半導体発光素子。 10. The semiconductor according to claim 9, wherein the bonding layer includes at least one element selected from the group consisting of Al, Ti, Zn, Zr, Nb, Mg, Bi, Si, Hf, and Ta. Light emitting element.
  11. 　前記接合層が、Ｔａ、Ｎｂ、Ｔｉからなる群より選ばれた少なくとも一種の元素を含んでいることを特徴とする請求項１０記載の半導体発光素子。 11. The semiconductor light emitting device according to claim 10, wherein the bonding layer contains at least one element selected from the group consisting of Ta, Nb, and Ti.
  12. 　前記接続電極が、Ａｕ、Ａｌまたはこれらの金属のいずれかを含む合金からなるボンディング層を有していることを特徴とする請求項９記載の半導体発光素子。 10. The semiconductor light emitting device according to claim 9, wherein the connection electrode has a bonding layer made of Au, Al, or an alloy containing any of these metals.
  13. 　前記接続電極が、前記接合層と前記ボンディング層との間に積層されるバリア層をさらに備え、
    　前記バリア層が、Ａｇ、Ａｌ、Ｒｕ、Ｒｈ、Ｐｄ、Ｏｓ、Ｉｒ、Ｐｔ、Ｔｉ、Ｗ、Ｍｏ、Ｎｉ、Ｃｏ、Ｚｒ、Ｈｆ、Ｔａ、Ｎｂのうちの何れかまたはこれら金属の何れかを含む合金からなるものであることを特徴とする請求項１２記載の半導体発光素子。     The connection electrode further comprises a barrier layer laminated between the bonding layer and the bonding layer;
    The barrier layer is made of Ag, Al, Ru, Rh, Pd, Os, Ir, Pt, Ti, W, Mo, Ni, Co, Zr, Hf, Ta, Nb, or any of these metals. 13. The semiconductor light emitting device according to claim 12, wherein the semiconductor light emitting device is made of an alloy containing the same.
  14. 　第１の導電型を有する第１の半導体層と、
    　前記第１の半導体層の上に積層される発光層と、
    　前記発光層の上に積層され、前記第１の導電型とは逆の第２の導電型を有する第２の半導体層と、
    　前記第２の半導体層の上に積層され、インジウム酸化物を含むとともに前記発光層から出力される光に対し透光性を有する透明電極と、
    　弁作用金属より選ばれた少なくとも一種の元素を含むとともに前記透明電極と接する側が当該元素の酸化物または窒化物の少なくともいずれか一方を含むように当該透明電極上に積層される第１の接合層と、
    　前記第１の接合層上に積層されて外部との電気的な接続に用いられる第１の接続電極と、
    　弁作用金属より選ばれた少なくとも一種の元素を含むとともに前記第１の半導体層と接する側が当該元素の酸化物または窒化物の少なくともいずれか一方を含むように前記第１の半導体層上に積層される第２の接合層と、
    　前記第２の接合層上に積層されて外部との電気的な接続に用いられる第２の接続電極と
    を有する半導体発光素子。     A first semiconductor layer having a first conductivity type;
    A light emitting layer laminated on the first semiconductor layer;
    A second semiconductor layer stacked on the light emitting layer and having a second conductivity type opposite to the first conductivity type;
    A transparent electrode that is stacked on the second semiconductor layer, contains indium oxide, and is transparent to light output from the light emitting layer;
    A first bonding layer including at least one element selected from valve metals and laminated on the transparent electrode so that a side in contact with the transparent electrode includes at least one of an oxide or a nitride of the element When,
    A first connection electrode stacked on the first bonding layer and used for electrical connection with the outside;
    It is laminated on the first semiconductor layer so as to contain at least one element selected from valve metals and at least one of an oxide or a nitride of the element on the side in contact with the first semiconductor layer. A second bonding layer,
    A semiconductor light emitting element having a second connection electrode stacked on the second bonding layer and used for electrical connection with the outside.
  15. 　前記第１の半導体層は電子をキャリアとするｎ型半導体層からなり、
    　前記第２の半導体層は正孔をキャリアとするｐ型半導体層からなること
    を特徴とする請求項１４記載の半導体発光素子。     The first semiconductor layer is an n-type semiconductor layer using electrons as carriers,
    15. The semiconductor light emitting element according to claim 14, wherein the second semiconductor layer is a p-type semiconductor layer using holes as carriers.
  16. 　前記第１の接合層および前記第２の接合層が、Ａｌ、Ｔｉ、Ｚｎ、Ｚｒ、Ｎｂ、Ｗ、Ｍｇ、Ｂｉ、Ｓｉ、Ｈｆ、Ｔａからなる群より選ばれた少なくとも一種の元素を含んでいることを特徴とする請求項１４記載の半導体発光素子。 The first bonding layer and the second bonding layer include at least one element selected from the group consisting of Al, Ti, Zn, Zr, Nb, W, Mg, Bi, Si, Hf, and Ta. 15. The semiconductor light emitting element according to claim 14, wherein
  17. 　前記第１の接合層および前記第２の接合層が、同じ元素の酸化物または窒化物を含んで構成されることを特徴とする請求項１４記載の半導体発光素子。 15. The semiconductor light emitting element according to claim 14, wherein the first bonding layer and the second bonding layer include an oxide or a nitride of the same element.
  18. 　前記第１の接続電極および前記第２の接続電極が、同じ金属または同じ合金を含んで構成されることを特徴とする請求項１４記載の半導体発光素子。 15. The semiconductor light emitting device according to claim 14, wherein the first connection electrode and the second connection electrode include the same metal or the same alloy.
  19. 　前記透明電極が、前記インジウム酸化物および亜鉛酸化物を含んで構成されることを特徴とする請求項１４記載の半導体発光素子。 15. The semiconductor light emitting element according to claim 14, wherein the transparent electrode includes the indium oxide and zinc oxide.
  20. 　前記第１の半導体層、前記発光層および前記第２の半導体層が、ＩＩＩ族窒化物半導体にて構成されていることを特徴とする請求項１４記載の半導体発光素子。 15. The semiconductor light emitting element according to claim 14, wherein the first semiconductor layer, the light emitting layer, and the second semiconductor layer are made of a group III nitride semiconductor.
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